Double balanced FET mixer with high IP3 and IF response down to DC levels

Claim 2

1 . A double balanced mixer for mixing an RF input signal with a local oscillator signal to provide at an output an intermediate frequency signal with a high third order intercept point and an intermediate frequency response down to direct current levels, comprising: a) a local oscillator terminal, an RF terminal and an intermediate frequency terminal; b) a pair of field effect transistors each having a gate, a drain and a source electrode, the source electrodes of the first and second transistors connected together; c) a first balun transformer connected between the local oscillator terminal and the gates; and d) a second balun transformer connected between the drains and the RF terminal and the intermediate frequency terminal.

Claim 3

2 . The double balanced mixer according to claim 1 , further comprising: a) the first transformer having a first, second third and fourth winding; b) the first winding connected between a first gate electrode and the local oscillator terminal; c) the second winding connected between a ground and a junction of the fourth winding and the ground; d) the third winding connected between the ground and a junction of the first winding and the local oscillator terminal; and e) the fourth winding connected between a second gate electrode and the ground.

Claim 4

3 . The double balanced mixer according to claim 1 , wherein the sources are connected to a ground.

Claim 5

4 . The double balanced mixer according to claim 1 , wherein an inductor is connected between the local oscillator terminal and a ground.

Claim 6

5 . The double balanced mixer according to claim 1 , wherein the intermediate frequency response goes to direct current levels.

Claim 7

6 . The double balanced mixer according to claim 1 , wherein the mixer is used in an in-phase quadrature modulator.

Claim 8

7 . The double balanced mixer according to claim 1 further comprising: a) the second transformer having a first, second, third, fourth, fifth and sixth winding; b) the first winding connected between the third winding and the RF terminal; c) the second winding connected between a ground and the sixth winding; d) the third winding connected between the ground and the first winding; e) the fourth winding connected between the intermediate frequency terminal and a first drain electrode; f) the fifth winding connected between the intermediate frequency terminal and a second drain electrode; and g) the sixth winding connected between the ground and the second winding.

Claim 9

8 . A double balanced mixer for mixing an RF input signal with a local oscillator signal to provide at an output an intermediate frequency signal with a high third order intercept point and an intermediate frequency response down to direct current levels, comprising: a) a local oscillator terminal, an RF terminal and an intermediate frequency terminal; b) a first, second, third and fourth field effect transistor, each transistor having a gate, a drain and a source electrode, the source electrodes of the first and third transistors connected together and to ground, the source electrodes of the second and third transistors connected together; c) a first balun transformer connected between the local oscillator terminal and the gate electrodes of the first, second third and fourth transistors; and d) a second balun transformer connected between the drain electrodes of the first, second, third and fourth transistor and the RF terminal and the intermediate frequency terminal.

Claim 10

8 . A double balanced mixer for mixing an RF input signal with a local oscillator signal to provide at an output an intermediate frequency signal with a high third order intercept point and an intermediate frequency response down to direct current levels, comprising: a) a local oscillator terminal, an RF terminal and an intermediate frequency terminal; b) a first, second, third and fourth field effect transistor, each transistor having a gate, a drain and a source electrode, the source electrodes of the first and third transistors connected together and to ground, the source electrodes of the second and third transistors connected together; c) a first balun transformer connected between the local oscillator terminal and the gate electrodes of the first, second third and fourth transistors; and d) a second balun transformer connected between the drain electrodes of the first, second, third and fourth transistor and the RF terminal and the intermediate frequency terminal.

Claim 11

9 . The double balanced mixer according to claim 8 , further comprising: a) the first transformer having a first, second third and fourth winding; b) the first winding connected between the gate electrodes of the second and third transistors and the local oscillator terminal; c) the second winding connected between a ground and a junction of the fourth winding and the ground; d) the third winding connected between the ground and a junction of the first winding and the local oscillator terminal; and e) the fourth winding connected between the gate electrodes of the first and fourth transistors and a junction of the local oscillator terminal and the ground.

Claim 12

10 . The double balanced mixer according to claim 8 , further comprising: a) the second transformer having a first, second, third, fourth, fifth and sixth winding; b) the first winding connected between the third winding and the RF terminal; c) the second winding connected between a ground and the sixth winding; d) the third winding connected between the ground and the first winding; e) the fourth winding connected between the intermediate frequency terminal and the drain electrodes of the third and fourth transistors; f) the fifth winding connected between the intermediate frequency terminal and the drain electrodes of the first and second transistors; and g) the sixth winding connected between the ground and the second winding.

Claim 13

11 . The double balanced mixer according to claim 8 , wherein all the source electrodes are connected to a ground.

Claim 14

12 . The double balanced mixer according to claim 8 , wherein an inductor is connected between the local oscillator terminal and a ground.

Claim 15

13 . The double balanced mixer according to claim 8 , wherein the intermediate frequency response goes to direct current levels.

Claim 16

14 . The double balanced mixer according to claim 8 , wherein the mixer is used in an in-phase quadrature modulator.

Claim 17

15 . The double balanced mixer according to claim 8 , further comprising: a) a fifth field effect transistor connected in parallel to the first field effect transistor; b) a sixth field effect transistor connected in parallel to the second field effect transistor; c) a seventh field effect transistor connected in parallel to the third field effect transistor; and d) an eighth field effect transistor connected in parallel to the fourth field effect transistor.

Claim 18

16 . A double balanced mixer, comprising: a) a local oscillator terminal, an RF terminal and an intermediate frequency terminal; b) a first field effect transistor having a first gate, a first drain and a first source; c) a second field effect transistor having a second gate, a second drain and a second source, the first and second sources connected together to a ground; d) a local oscillator balun transformer connected between the local oscillator terminal and the gates; e) an intermediate frequency balun transformer connected between the drains and the intermediate frequency terminal; and f) a RF balun transformer connected between the drains and the RF terminal.

Claim 19

16 . A double balanced mixer, comprising: a) a local oscillator terminal, an RF terminal and an intermediate frequency terminal; b) a first field effect transistor having a first gate, a first drain and a first source; c) a second field effect transistor having a second gate, a second drain and a second source, the first and second sources connected together to a ground; d) a local oscillator balun transformer connected between the local oscillator terminal and the gates; e) an intermediate frequency balun transformer connected between the drains and the intermediate frequency terminal; and f) a RF balun transformer connected between the drains and the RF terminal.

Claim 20

17 . The double balanced mixer according to claim 16 wherein the intermediate frequency balun transformer and the RF balun transformer are wound on a common core.

Claim 21

18 . The double balanced mixer according to claim 16 wherein the intermediate frequency balun transformer and the RF balun transformer are wound on two separate cores.

Claim 22

19 . The double balanced mixer according to claim 16 wherein the intermediate frequency response goes to direct current levels.

Claim 23

20 . The double balanced mixer according to claim 16 wherein a third and fourth field effect transistor are connected in parallel with the first and second field effect transistors.

Claim 24

21 . The double balanced mixer according to claim 20 wherein the parallel field effect transistors have a lower RF power through the transistors, the lower RF power resulting a high value of IP3.

Claim 25

22 . A double balanced mixer having a local oscillator terminal for receiving a local oscillator signal, an RF terminal for receiving an RF signal and an intermediate frequency terminal for providing an intermediate frequency signal, the double balanced mixer comprising: a) a first and second pair of parallel connected field effect transistors each having a gate, a drain and a source; b) the sources of the first pair of transistors connected together to a ground; c) the sources of the second pair of transistors connected together; d) a local oscillator balun transformer connected between the local oscillator terminal and the gates; e) an intermediate frequency balun transformer connected between the drains and the intermediate frequency terminal; and f) a RF balun transformer connected between the drains and the RF terminal.

Claim 26

22 . A double balanced mixer having a local oscillator terminal for receiving a local oscillator signal, an RF terminal for receiving an RF signal and an intermediate frequency terminal for providing an intermediate frequency signal, the double balanced mixer comprising: a) a first and second pair of parallel connected field effect transistors each having a gate, a drain and a source; b) the sources of the first pair of transistors connected together to a ground; c) the sources of the second pair of transistors connected together; d) a local oscillator balun transformer connected between the local oscillator terminal and the gates; e) an intermediate frequency balun transformer connected between the drains and the intermediate frequency terminal; and f) a RF balun transformer connected between the drains and the RF terminal.

Claim 27

23 . The double balanced mixer according to claim 22 wherein the intermediate frequency balun transformer and the RF balun transformer are wound on a common core.

Claim 28

24 . The double balanced mixer according to claim 22 wherein the intermediate frequency response goes to direct current levels.

Claim 29

25 . The double balanced mixer according to claim 22 wherein the first pair of parallel connected field effect transistors comprises a first and second field effect transistor and the second pair of parallel connected field effect transistors comprises a third and fourth field effect transistor.

Claim 30

26 . The double balanced mixer according to claim 25 , further comprising: a) a first, second, third and fourth winding forming the local oscillator balun transformer; b) the first winding connected between the gate electrodes of the second and third transistors and the local oscillator terminal; c) the second winding connected between a ground and a junction of the fourth winding and the ground; d) the third winding connected between the ground and a junction of the first winding and the local oscillator terminal; and e) the fourth winding connected between the gate electrodes of the first and fourth transistors and a junction of the local oscillator terminal and the ground.

Claim 31

27 . The double balanced mixer according to claim 25 , further comprising: a) a first and second winding forming the RF balun transformer; b) a third, fourth, fifth and sixth winding forming the intermediate frequency balun transformer; c) the first winding connected between the third winding and the RF terminal; d) the second winding connected between a ground and the sixth winding; e) the third winding connected between the ground and the first winding; f) the fourth winding connected between the intermediate frequency terminal and the drain electrodes of the third and fourth transistors; g) the fifth winding connected between the intermediate frequency terminal and the drain electrodes of the first and second transistors; and h) the sixth winding connected between the ground and the second winding.

Claim 32

28 . The double balanced mixer according to claim 22 , wherein there is a DC path for the intermediate frequency signal.

Claim 33

29 . The double balanced mixer according to claim 1 , wherein there is a DC path for the intermediate frequency signal.