Polarization diversity system suitable for radio communication in indoor space

Claim 2

A polarization diversity system suitable for radio communication in indoor space, comprising: a transmitter including a plurality of transmission antennas of different main polarization components, at least two of said transmission antennas being so disposed that their main polarization components intersect each other at right angles; a transmission circuit connected to said transmission antennas; an antenna change-over circuit between said transmission antennas and said transmission circuit which connects the transmission circuit to each of said transmission antennas for transmitting a series of data through each of the transmission antennas having different polarization components; and a receiver remote from said transmitter including a means for receiving electromagnetic waves consisting of a single reception antenna the series of data transmitted through each of the transmission antennas having different polarization components; wherein said transmitter and said receiver are disposed at mutually remote positions in indoor space such that the transmitter transmits the series of data antennas, the series of data transmitted through each of the transmission antennas being propagated through any one of a plurality of propagation paths produced in the indoor space at different timing with different polarization components and the receiver reproduces the series of data transmitted from the transmitter through any one of the following of transmission antennas through one of said propagation paths in the indoor space and received through the single reception antenna.

Claim 3

A polarization diversity system suitable for radio communication in indoor space, comprising: a transmitter including a plurality of transmission antennas of different main polarization components, at least two of the transmission antennas being so disposed that their main polarization components intersect each other at right angles, each of the transmission antennas including: (a) an annular conductor discontinued at a portion and having first and second ends at that portion, (b) a tuning capacitor inserted between both ends of the annular conductor at the discontinued portion, (c) an inductance element having first and second ends and connected to the annular conductor at the first end of the inductance element, (d) a conductive wire having first and second ends and connected at the first end to the second end of the inductance element and discontinued at the second end of the wire, and (e) power-supplying and grounding points provided on the annular conductor, the annular conductor and conductive wire being disposed for producing a radiation from the annular conductor and a further radiation due to spatial coupling between the annular and conductive wire and for achieving substantially isotropic composite directivity; a transmission circuit connected to said transmission antennas; an antenna change-over circuit between said transmission antennas and said transmission circuit which connects the transmission circuit to a selected one of said transmission antennas for transmitting a series of data through each of the transmission antennas; and a receiver remote from said transmitter including a single reception antenna; wherein said transmitter and said receiver are located at mutually remote positions in indoor space such that the transmitter transmits the series of data sequentially through a selected one of the transmission antennas, and the receiver reproduces the series of data when the data transmitted from the transmitter through any one of the plurality of transmission antennas are received through the single reception antenna.

Claim 4

A polarization diversity system suitable for radio communication in indoor space, comprising: a transmitter including a plurality of transmission antennas of different main polarization components, at least two of the transmission antennas being so disposed that their main polarization components intersect each other at right angles, each of the transmission antennas including: (a) an annular conductor discontinued at a portion and having first and second ends at that portion, (b) a tuning capacitor inserted between both ends of the annular conductor at the discontinued portion, (c) an inductance element having first and second ends and connected to the annular conductor at the first end of the inductance element, (d) a conductive wire having first and second ends and connected at the first end to the second end of the inductance element and discontinued at the second end of the wire, and (e) power-supplying and grounding points provided on the annular conductor, the annular conductor and conductive wire being disposed for producing a radiation from the annular conductor and a further radiation due to spatial coupling between the annular and conductive wire and for achieving substantially isotropic composite directivity; a transmission circuit connected to said transmission antennas; an antenna change-over circuit between said transmission antennas and said transmission circuit which connects the transmission circuit to a selected one of said transmission antennas for transmitting a series of data through each of the transmission antennas; and a receiver remote from said transmitter including a single reception antenna; wherein said transmitter and said receiver are located at mutually remote positions in indoor space such that the transmitter transmits the series of data sequentially through a selected one of the transmission antennas, and the receiver reproduces the series of data when the data transmitted from the transmitter through any one of the plurality of transmission antennas are received through the single reception antenna.

Claim 5

A system according to claim 2 wherein each of said transmission antennas includes antennas loops which intersect each other perpendicularly, thus causing their respective polarization components to intersect each other perpendicularly.

Claim 6

A system according to claim 2 wherein each of said transmission antennas include: a diode connected to said tuning capacitor for allowing said antenna change-over circuit to determine ON and OFF operation of the antennas by means of a biasing current to said diode.

Claim 7

A system according to claim 4 wherein said diode is connected in parallel with said tuning capacitor for carrying out the ON and OFF operation of said antennas in response to said biasing current fed to said diode.

Claim 8

A system according to claim 4 wherein said diode is connected in series with said tuning capacitor for turning said antennas ON and OFF in response to said biasing current fed to the diode.