Electrically scanning microwave radiometer

Claim 2

An electrically scanning microwave radiometer for measuring the brightness temperature of an object by performing conical scanning of the object comprising: reflector means having a focal line of predetermined configuration; an array of N×M radiators arranged along the focal line of said reflector means, where M and N are integers, M being more than two and N being more than one, said radiators being grouped to form a number N of subarrays each including M adjacent radiators; a number N of beam switching means provided in correspondence with said respective subarrays and operable to switch beams formed by said radiators correspondingly selected from said respective subarrays to output a different set of N signals sequentially; and signal processing means for receiving and arithmetically operating the sequentially output sets of N signals from said N beam switching means to obtain the brightness temperature value of the object located within the width of the antenna beam, thereby suppressing the variation of the brightness temperature value and making the value of temperature resolution smaller.

Claim 3

Radiometer as claimed in claim 1, further comprising N×M frequency selective means each receiving the output from a corresponding one of said radiators so as to output signals having different frequencies, and wherein N beam switching means, N low-noise receivers, N integrators and one signal processing unit are provided for each of said different frequencies, thereby enabling simultaneous measurements at multiple frequencies to be performed.

Claim 4

Radiometer as claimed in claim 2 wherein said reflector means comprises torus-type reflector means, and the focal line is a circular focal line.

Claim 5

Radiometer as claimed in claim 1, further comprising N×M polarization and frequency selective means, each being adapted to receive the output from a corresponding one of the radiators in said N subarrays so as to output orthogonally polarized signals having different frequencies, wherein N beam switching means, N low-noise receivers, N integrators and one signal processing unit are provided for each frequency and each polarization, thereby enabling simultaneous measurements with different frequencies and with different polarizations to be performed.

Claim 6

Radiometer as claimed in claim 4 wherein said reflector means comprises torus-type reflector means, and the focal line is a circular focal line.

Claim 7

Radiometer as claimed in claim 1 wherein said signal processing means comprises: N low-noise receiver, each receiving the ouptut from a corresponding one of said N beam switching means to amplify and detect the received output; N integrators, each receiving and integrating the detected signal output from a corresponding one of said N low-noise receivers to obtain the average brightness temperature value of the object; and a signal processing unit for receiving and combining the integrated signals output from said N integrators of obtain the brightness temperature value of the object.

Claim 8

Radiometer as claimed in claim 6, further comprising N×M polarization selective means each connected to the output of a corresponding one of said radiators so as to output orthogonally polarized signals, and wherein said N beam switching means, N low-noise receivers and N integrators and one signal processing unit are provided for each of said orthogonally polarized signals, thereby enabling simultaneous measurements with different polarizations to be performed.

Claim 9

Radiometer as claimed in claim 6, further comprising N×M frequency selective means each receiving the output from a corresponding one of said radiators so as to output signals having different frequencies, and wherein said N beam switching means, N low-noise receivers, N integrators and one signal processing unit are provided for each of said different frequencies, thereby enabling simultaneous measurements at multiple frequencies to be performed.

Claim 10

Radiometer as claimed in claim 6, further comprising N×M polarization and frequency selective means, each being adapted to receive the output from a corresponding one of the radiators in said N subarrays so as to output orthogonally polarized signals having different frequencies, wherein said N beam switching means, N low-noise receivers, N integrators and one signal processing unit are provided for each frequency and each polarization, thereby enabling simultaneous measurements with different frequencies and with different polarizations to be performed.

Claim 11

Radiometer as claimed in claim 1 wherein said reflector means comprises torus-type reflector means, and the focal line is a circular focal line.

Claim 12

An electrically scanning microwave radiometer for measuring the brightness temperature of an object by performing conical scanning of the object comprising: torus-type reflector means having a circular focal line; an array of N×M radiators arranged along the circular focal line of said reflector means, where M and N are integers, M being more than two and N being more than one, said radiators being grouped to form a number N of subarrays each including M adjacent radiators; a number N of tournament-type beam switching means respectively connected to the outputs of the radiators in a corresponding one of said N subarrays and operable to switch beams formed by said radiators correspondingly selected from said respective subarrays to output a different set of N signals sequentially; and signal processing means for receiving and arithmetically operating the sequentially output sets of N signals from said N beam switching means to obtain the brightness temperature value of the object located within the width of the antenna beam, thereby suppressing the variation of the brightness temperature value and making the value of temperature resolution smaller.

Claim 13

An electrically scanning microwave radiometer for measuring the brightness temperature of an object by performing conical scanning of the object comprising: torus-type reflector means having a circular focal line; an array of N×M radiators arranged along the circular focal line of said reflector means, where M and N are integers, M being more than two and N being more than one, said radiators being grouped to form a number N of subarrays each including M adjacent radiators; a number N of tournament-type beam switching means respectively connected to the outputs of the radiators in a corresponding one of said N subarrays and operable to switch beams formed by said radiators correspondingly selected from said respective subarrays to output a different set of N signals sequentially; and signal processing means for receiving and arithmetically operating the sequentially output sets of N signals from said N beam switching means to obtain the brightness temperature value of the object located within the width of the antenna beam, thereby suppressing the variation of the brightness temperature value and making the value of temperature resolution smaller.

Claim 14

Radiometer as claimed in claim 11 wherein each said tournament-type beam switching means is comprised of a plurality of switching arrays coupled in series with each successive array being smaller than the preceding array.

Claim 15

Radiometer as claimed in claim 11 wherein said signal processing means comprises: N low-noise receivers, each receiving the output from a corresponding one of said N beam switching means to amplify and detect the received output; N integrators, each receiving and integrating the detected signal output from a corresponding one of said N low-noise receivers to obtain the average brightness temperature value of the object; and a signal processing unit for receiving and combining the intergrated signals output from said N integrators to obtain the brightness temperature value of the object.

Claim 16

Radiometer as claimed in claim 13, further comprising N×M polarization selective means each connected to the output of a corresponding one of said radiators so as to output orthogonally polarized signals, and wherein said N beam switching means, N low-noise receivers and N integrators and one signal processing unit are provided for each of said orthogonally polarized signals, thereby enabling simultaneous measurements with different polarizations to be performed.

Claim 17

Radiometer as claimed in claim 14 wherein each of said tournament-type beam switching means comprises ferrite switches connected in a tournament manner.

Claim 18

Radiometer as claimed in claim 14 wherein each of said tournament-type beam switching means comprises PIN diode switches connected in a tournament manner.

Claim 19

Radiometer as claimed in claim 13, further comprising N×M frequency selective means each receiving the output from a corresponding one of said radiators so as to output signals having different frequencies, and wherein said N beam switching means, N low-noise receivers, N integrators and one signal processing unit are provided for each of said different frequencies, thereby enabling simultaneous measurements at multiple frequencies to be performed.

Claim 20

Radiometer as claimed in claim 17 wherein each of said tournament-type beam switching means comprising ferrite switches connected in a tournament manner.

Claim 21

Radiometer as claimed in claim 17 wherein each of said tournament-type beam switching means comprises PIN diode switches connected in a tournament manner.

Claim 22

Radiometer as claimed in claim 13, further comprising N×M polarization and frequency selective means, each being adapted to receive the output from a corresponding one of the radiators in said N subarrays so as to output orthogonally polarized signals having different frequencies, wherein said N beam switching means, N low-noise receivers, N integrators and one signal processing unit are provided for each frequency and each polarization, thereby enabling simultaneous measurements with different frequencies and with different polarizations to be performed.

Claim 23

Radiometer as claimed in claim 20 wherein each of said tournament-type beam switching means comprises ferrite switches connected in a tournament manner.

Claim 24

Radiometer as claimed in claim 20 wherein each of said tournament-type beam switching means comprises PIN diode switches connected in a tournament manner.

Claim 25

An electrically scanning microwave radiometer for measuring the brightness temperature of an object at multiple frequencies by performing conical scanning of the object comprising: torus-type reflector means having a circular focal line; a number L of arrays, each including N×M radiators arranged along the circular focal line of said reflector means, where L, M and N are integers, L and M being more than two and N being more than one, said radiators in each of said L arrays being grouped to form a number N of subarrays each including M adjacent radiators; a number L×N×M of frequency selective means, each receiving the output from a corresponding one of said radiators in said N subarrays of the respective L arrays so as to output signals having different frequencies; a number L×N of tournament-type beam switching means provided in correspondence with said L×N subarrays to respectively receive the outputs from the frequency selective means connected to a corresponding one of said L×N subarrays, and operable to allow beams formed at said different frequencies by said radiators correspondingly selected from said L×N subarrays to be switched to sequentially output a set of L×N signals for each frequency; and signal processing means for receiving and arithmetically operating the sets of L×N signals sequentially output for each frequency from said L×N beam switching means to obtain the brightness temperature value of the object located within the width of the antenna beam, thereby enabling simultaneous measurements at multiple frequencies to be performed, suppressing the variation of the brightness temperature value and making the value of temperature resolution smaller.

Claim 26

An electrically scanning microwave radiometer for measuring the brightness temperature of an object at multiple frequencies by performing conical scanning of the object comprising: torus-type reflector means having a circular focal line; a number L of arrays, each including N×M radiators arranged along the circular focal line of said reflector means, where L, M and N are integers, L and M being more than two and N being more than one, said radiators in each of said L arrays being grouped to form a number N of subarrays each including M adjacent radiators; a number L×N×M of frequency selective means, each receiving the output from a corresponding one of said radiators in said N subarrays of the respective L arrays so as to output signals having different frequencies; a number L×N of tournament-type beam switching means provided in correspondence with said L×N subarrays to respectively receive the outputs from the frequency selective means connected to a corresponding one of said L×N subarrays, and operable to allow beams formed at said different frequencies by said radiators correspondingly selected from said L×N subarrays to be switched to sequentially output a set of L×N signals for each frequency; and signal processing means for receiving and arithmetically operating the sets of L×N signals sequentially output for each frequency from said L×N beam switching means to obtain the brightness temperature value of the object located within the width of the antenna beam, thereby enabling simultaneous measurements at multiple frequencies to be performed, suppressing the variation of the brightness temperature value and making the value of temperature resolution smaller.

Claim 27

The radiometer as claimed in claim 23 wherein said signal processing means comprises: a number L×N of low-noise receivers, each receiving the output from a corresponding one of said L×N beam switching means to amplify and detect the received output; a number L×N of integrators, each receiving and integrating the detected signal output from a corresponding one of said low-noise receivers to obtain the average brightness temperature value of the object; and a number L of signal processing units, each receiving and combining the integrated signals output from said N integrators provided in correspondence with each of said L arrays to obtain the brightness temperature value of the object.

Claim 28

Radiometer as claimed in claim 24 wherein each of said tournament-type beam switching means comprises ferrite switches connected in a tournament manner.

Claim 29

Radiometer as claimed in claim 24 wherein each of said tournament-type beam switching means comprises PIN diode switches connected in a tournament manner.

Claim 30

An electrically scanning microwave radiometer for measuring the brightness temperature of an object at multiple frequencies with two orthogonal polarizations by performing conical scanning of the object comprising: torus-type reflector means having a circular focal line; a number L of arrays, each including a number N×M of radiators arranged along the circular focal line of said reflector means, where L, M and N are integers, L and M being more than two and N being more than one, said radiators in each of said L arrays being grouped to form a number N of subarrays each including M adjacent radiators; a number L×N×M of polarization and frequency selective means, each receiving the output from a corresponding one of said radiators in said N subarrays of the respective L arrays so as to output orthogonally polarized signals having different frequencies; a number L×N of tournament-type beam switching means provided in correspondence with said N subarrays of said L arrays to respectively receive the outputs from the polarization and frequency selective means connected to a corresponding one of said L×N subarrays, and operable to allow beams formed at said different frequencies by said radiators correspondingly selected from said L×N subarrays to be switched to sequentially output a different set of L×N signals for each frequency and polarization; and signal processing means for receiving and arithmetically operating the sets of L×N signals sequentially output for each frequency and polarization from said L×N beam switching means to obtain the brightness temperature value of the object located within the width of the antenna beam, thereby enabling simultaneous measurements at multiple frequencies with orthogonal polarizations to be performed, suppressing the variation of the brightness temperature value and making the value of temperature resolution smaller.

Claim 31

An electrically scanning microwave radiometer for measuring the brightness temperature of an object at multiple frequencies with two orthogonal polarizations by performing conical scanning of the object comprising: torus-type reflector means having a circular focal line; a number L of arrays, each including a number N×M of radiators arranged along the circular focal line of said reflector means, where L, M and N are integers, L and M being more than two and N being more than one, said radiators in each of said L arrays being grouped to form a number N of subarrays each including M adjacent radiators; a number L×N×M of polarization and frequency selective means, each receiving the output from a corresponding one of said radiators in said N subarrays of the respective L arrays so as to output orthogonally polarized signals having different frequencies; a number L×N of tournament-type beam switching means provided in correspondence with said N subarrays of said L arrays to respectively receive the outputs from the polarization and frequency selective means connected to a corresponding one of said L×N subarrays, and operable to allow beams formed at said different frequencies by said radiators correspondingly selected from said L×N subarrays to be switched to sequentially output a different set of L×N signals for each frequency and polarization; and signal processing means for receiving and arithmetically operating the sets of L×N signals sequentially output for each frequency and polarization from said L×N beam switching means to obtain the brightness temperature value of the object located within the width of the antenna beam, thereby enabling simultaneous measurements at multiple frequencies with orthogonal polarizations to be performed, suppressing the variation of the brightness temperature value and making the value of temperature resolution smaller.

Claim 32

Radiometer as claimed in claim 27 wherein said signal processing means comprises: a number l×N of low-noise receivers, each receiving the output from a corresponding one of said L×N beam switching means to amplify and detect the received output; a number L×N of integrators, each receiving and integrating the detected signal output from a corresponding one of said low-noise receivers to obtain the average brightness temperature value of the object; and a number L of signal processing units, each receiving and combining the integrated signals output from said N integrators provided in correspondence with each of said L arrays to obtain the brightness temperature value of the object.

Claim 33

Radiometer as claimed in claim 28 wherein each of said tournament-type beam switching means comprises ferrite switches connected in a tournament manner.

Claim 34

Radiometer as claimed in claim 28 wherein each of said tournament-type beam switching means comprises PIN diode switches connected in a tournament manner.

Claim 35

An electrically scanning microwave radiometer for measuring the brightness temperature of an object by performing conical scanning of the object comprising: torus-type reflector means having a circular focal line; an array of N×M radiators arranged along the circular focal line of said reflector means, where M and N are integers, M being more than two and N being more than one, said radiators being grouped to form a number N of subarrays each including M adjacent radiators; a number N of beam switching means, each comprising a multiply branching switching array, respectively connected to the outputs of the radiators in a corresponding one of said N subarrays and operable to switch beams formed by said radiators correspondingly selected from said respective subarrays to output a different set of N signals sequentially; and signal processing means for receiving and arithmetically operating the sequentially output sets of N signals from said N beam switching means to obtain the brightness temperature value of the object located within the width of the antenna beam, thereby suppressing the variation of the brightness temperature value and making the value of temperature resolution smaller.

Claim 36

An electrically scanning microwave radiometer for measuring the brightness temperature of an object by performing conical scanning of the object comprising: torus-type reflector means having a circular focal line; an array of N×M radiators arranged along the circular focal line of said reflector means, where M and N are integers, M being more than two and N being more than one, said radiators being grouped to form a number N of subarrays each including M adjacent radiators; a number N of beam switching means, each comprising a multiply branching switching array, respectively connected to the outputs of the radiators in a corresponding one of said N subarrays and operable to switch beams formed by said radiators correspondingly selected from said respective subarrays to output a different set of N signals sequentially; and signal processing means for receiving and arithmetically operating the sequentially output sets of N signals from said N beam switching means to obtain the brightness temperature value of the object located within the width of the antenna beam, thereby suppressing the variation of the brightness temperature value and making the value of temperature resolution smaller.

Claim 37

Radiometer as claimed in claim 31 wherein said multiply branching switching array comprises a multiply bilaterally branching switching array.

Claim 38

Radiometer as claimed in claim 31 wherein said signal processing means comprises: N low-noise receivers, each receiving the output from a corresponding one of said N beam switching means to amplify and detect the received output; N integrators, each receiving and integrating the detected signal output from a corresponding one of said N low-noise receivers to obtain the average brightness temperature value of the object; and a signal processing unit for receiving and combining the integrated signals output from said N integrators to obtain the brightness temperature value of the object.

Claim 39

Radiometer as claimed in claim 33, further comprising N×M polarization selective means each connected to the output of a corresponding one of said radiators so as to output orthogonally polarized signals, and wherein said N beam switching means, N low-noise receivers and N integrators and one signal processing unit are provided for each of said orthogonally polarized signals, thereby enabling simultaneous measurements with different polarizations to be performed.

Claim 40

Radiometer as claimed in claim 34 wherein each of said beam switching means comprises ferrite switches connected in a repeatedly branching connection array to form the multiply branching switching array.

Claim 41

Radiometer as claimed in Claim 35 wherein said repeatedly branching connection array comprises a repeatedly bilaterally branching connection array.

Claim 42

Radiometer as claimed in claim 34 wherein each of said beam switching means comprises PIN diode switches connected in a repeatedly branching connection array to form the multiply branching switching array.

Claim 43

Radiometer as claimed in claim 37 wherein said repeatedly branching connection array comprises a repeatedly bilaterally branching connection array.

Claim 44

Radiometer as claimed in claim 33, further comprising N×M frequency selective means each receiving the output from a corresponding one of said radiators so as to output signals having different frequencies, and wherein said N beam switching means, N low-noise receivers, N integrators and one signal processing unit are provided for each of said different frequencies, thereby enabling simultaneous measurements at multiple frequencies to be performed.

Claim 45

Radiometer as claimed in claim 39 wherein each of said beam switching means comprises ferrite switches connected in a repeatedly branching connection array to form the multiply branching switching array.

Claim 46

Radiometer as claimed in claim 40 wherein said repeatedly branching connection array comprises a repeatedly bilaterally branching connection array.

Claim 47

Radiometer as claimed in claim 39 wherein each of said beam switching means comprises PIN diode switches connected in a repeatedly branching connection array to form the multiply branching switching array.

Claim 48

Radiometer as claimed in claim 42 wherein said repeatedly branching connection array comprises a repeatedly bilaterally branching connection array.

Claim 49

Radiometer as claimed in claim 33, further comprising N×M polarization and frequency selective means, each being adapted to receive the output from a corresponding one of the radiators in said N subarrays so as to output orthogonally polarized signals having different frequencies, wherein said N beam switching means, N low-noise receivers, N integrators and one signal processing unit are provided for each frequency and each polarization, thereby enabling simultaneous measurements with different frequencies and with different polarizations to be performed.

Claim 50

Radiometer as claimed in claim 44 wherein each of said beam switching means comprises ferrite switches connected in a repeatedly branching connection array to form the multiply branching switching array.

Claim 51

Radiometer as claimed in claim 45 wherein said repeatedly branching connection array comprises a repeatedly bilaterally branching connection array.

Claim 52

Radiometer as claimed in claim 39 wherein each of said beam switching means comprises PIN diode switches connected in a repeatedly branching connection array to form the multiple branching switching array.

Claim 53

Radiometer as claimed in claim 47 wherein said repeatedly branching connection array comprises a repeatedly bilaterally branching connection array.

Claim 54

An electrically scanning microwave radiometer for measuring the brightness temperature of an object at multiple frequencies by performing conical scanning of the object comprising: torus-type reflector means having a circular focal line; a number L of arrays, each including N×M radiators arranged along the circular focal line of said reflector means, where L, M and N are integers, L and M being more than two and N being more than one, said radiators in each of said L arrays being grouped to form a number N of subarrays each including M adjacent radiators; a number L×N×M of frequency selective means, each receiving the output from a corresponding one of said radiators in said N subarrays of the respective L arrays so as to output signals having different frequencies; a number L×N of beam switching means, each comprising a multiply branching switching array, provided in correspondence with said L×N subarrays to respectively receive the outputs from the frequency selective means connected to a corresponding one of said L×N subarrays, and operable to allow beams formed at said different frequencies by said radiators correspondingly selected from said L×N subarrays to be switched to sequentially output a set of L×N signals for each frequency; and signal processing means for receiving and arithmetically operating the sets of L×N signals sequentially output for each frequency from said L×N beam switching means to obtain the brightness temperature value of the object located within the width of the antenna beam, thereby enabling simultaneous measurements at multiple frequencies to be performed, suppressing the variation of the brightness temperature value and making the value of temperature resolution smaller.

Claim 55

An electrically scanning microwave radiometer for measuring the brightness temperature of an object at multiple frequencies by performing conical scanning of the object comprising: torus-type reflector means having a circular focal line; a number L of arrays, each including N×M radiators arranged along the circular focal line of said reflector means, where L, M and N are integers, L and M being more than two and N being more than one, said radiators in each of said L arrays being grouped to form a number N of subarrays each including M adjacent radiators; a number L×N×M of frequency selective means, each receiving the output from a corresponding one of said radiators in said N subarrays of the respective L arrays so as to output signals having different frequencies; a number L×N of beam switching means, each comprising a multiply branching switching array, provided in correspondence with said L×N subarrays to respectively receive the outputs from the frequency selective means connected to a corresponding one of said L×N subarrays, and operable to allow beams formed at said different frequencies by said radiators correspondingly selected from said L×N subarrays to be switched to sequentially output a set of L×N signals for each frequency; and signal processing means for receiving and arithmetically operating the sets of L×N signals sequentially output for each frequency from said L×N beam switching means to obtain the brightness temperature value of the object located within the width of the antenna beam, thereby enabling simultaneous measurements at multiple frequencies to be performed, suppressing the variation of the brightness temperature value and making the value of temperature resolution smaller.

Claim 56

Radiometer as claimed in claim 49 wherein said multiply branching switching array comprises a multiply bilaterally branching switching array.

Claim 57

Radiometer as claimed in claim 49 wherein said signal processing means comprises: a number L×N of low-noise receivers, each receiving the output from a corresponding one of said L×N beam switching means to amplify and detect the received output; a number L×N of integrators, each receiving and integrating the detected signal output from a corresponding one of said low-noise receivers to obtain the average brightness temperature value of the object; and a number L of signal processing units, each receiving and combining the integrated signals output from said N integrators provided in correspondence with each of said L arrays to obtain the brightness temperature value of the object.

Claim 58

Radiometer as claimed in claim 51 wherein said each of said beam switching means comprises ferrite switches connected in a repeatedly branching connection array to form the multiple branching switching array.

Claim 59

Radiometer as claimed in claim 52 wherein said repeatedly branching connection array comprising a repeatedly bilaterally branching connection array.

Claim 60

Radiometer as claimed in claim 51 wherein each of said beam switching means comprises PIN diode switches connected in a repeatedly branching connection array to form the multiply branching switching array.

Claim 61

Radiometer as claimed in claim 54 wherein said repeatedly branching connection array comprises a repeatedly bilaterally branching connection array.

Claim 62

An electrically scanning microwave radiometer for measuring the brightness temperature of an object of multiple frequencies with two orthogonal polarizations by performing conical scanning of the object comprising: torus-type reflector means having a circular focal line; a number L of arrays, each including a number N×M of radiators arranged along the circular focal line of said reflectors means, where L, M and N are integers, L and M being more than two and N being more than one, said radiators in each of said L arrays being grouped to form a number N of subarrays each including M adjacent radiators; a number L×N×M of polarization and frequency selective means, each receiving the output from a corresponding one of said radiators in said N subarrays of the respective L arrays so as to output orthogonally polarized signals having different frequencies; a number L×N of beam switching means, each comprising a multiply branching switching array, provided in correspondence with said N subarrays of said L arrays to respectively receive the outputs from the polarization and frequency selective means connected to a corresponding one of said L×N subarrays, and operable to allow beams formed at said different frequencies by said radiators correspondingly selected from said L×N subarrays to be switched to sequentially output a different set of L×N signals for each frequency and polarization; and signal processing means for receiving and arithmetically operating the sets of L×N signals sequentially output for each frequency and polarization from said L×N beam switching means to obtain the brightness temperature value of the object located within the width of the antenna beam, thereby enabling simultaneous measurements at multiple frequencies with orthogonal polarizations to be performed, suppressing the variation of the brightness temperature value and making the value of temperature resolution smaller.

Claim 63

An electrically scanning microwave radiometer for measuring the brightness temperature of an object of multiple frequencies with two orthogonal polarizations by performing conical scanning of the object comprising: torus-type reflector means having a circular focal line; a number L of arrays, each including a number N×M of radiators arranged along the circular focal line of said reflectors means, where L, M and N are integers, L and M being more than two and N being more than one, said radiators in each of said L arrays being grouped to form a number N of subarrays each including M adjacent radiators; a number L×N×M of polarization and frequency selective means, each receiving the output from a corresponding one of said radiators in said N subarrays of the respective L arrays so as to output orthogonally polarized signals having different frequencies; a number L×N of beam switching means, each comprising a multiply branching switching array, provided in correspondence with said N subarrays of said L arrays to respectively receive the outputs from the polarization and frequency selective means connected to a corresponding one of said L×N subarrays, and operable to allow beams formed at said different frequencies by said radiators correspondingly selected from said L×N subarrays to be switched to sequentially output a different set of L×N signals for each frequency and polarization; and signal processing means for receiving and arithmetically operating the sets of L×N signals sequentially output for each frequency and polarization from said L×N beam switching means to obtain the brightness temperature value of the object located within the width of the antenna beam, thereby enabling simultaneous measurements at multiple frequencies with orthogonal polarizations to be performed, suppressing the variation of the brightness temperature value and making the value of temperature resolution smaller.

Claim 64

Radiometer as claimed in claim 56 wherein said multiply branching switching array comprises a multiply bilaterally branching switching array.

Claim 65

Radiometer as claimed in claim 56 wherein said signal processing means comprises: a number L×N of low-noise receivers, each receiving the output from a corresponding one of said L×N beam switching means to amplify and detect the received output; a number L×N of integrators, each receiving and integrating the detected signal output from a corresponding one of said low-noise receivers to obtain the average brightness temperature value of the object; and a number L of signal processing units, each receiving and combining the integrated signals output from said N integrators provided in correspondence with each of said L arrays to obtain the brightness temperature value of the object.

Claim 66

Radiometer as claimed in claim 58 wherein each of said beam switching means comprises ferrite switches connected in a repeatedly branching connection array to form the multiply branching switching array.

Claim 67

Radiometer as claimed in claim 59 wherein said repeatedly branching connection array comprises a repeatedly bilaterally branching connection array.

Claim 68

Radiometer as claimed in claim 58 wherein each of said beam switching means comprises PIN diode switches connected in a repeatedly branching connection array to form the multiply branching switching array.

Claim 69

Radiometer as claimed in claim 61 wherein said repeatedly branching connection array comprises a repeatedly bilaterally branching connection array.