Switching power amplifier and DAC for an electronically-scanned array

1. An integrated circuit antenna array, comprising:

a low-voltage substrate;

a high-voltage substrate;

a digital-to-analog converter (DAC) integrated with the low-voltage substrate, the DAC being operable to receive a frequency command and convert it into an analog voltage;

a voltage-controlled oscillator (VCO) integrated with the low-voltage substrate, the VCO providing an RF signal having an output frequency responsive to the analog voltage;

a plurality of switching power amplifiers integrated with the high-voltage substrate, each switching power amplifier receiving an on/off RF signal from the low-voltage substrate and providing an amplified RF output signal; and

a plurality of antennas adjacent the high-voltage substrate corresponding to the plurality of switching power amplifiers, each antenna being operable to transmit the amplified RF output signal from its corresponding switching power amplifier.

2. The integrated circuit antenna array of claim 1 , further comprising:

a non-linear circuit operable to rectify the RF signal from the VCO into a substantially on/off RF signal; and

a switch operable to gate the substantially on/off RF signal into gated pulses responsive to a gating command.

3. The integrated circuit antenna array of claim 2 , further comprising:

a plurality of phase-shifters corresponding to the plurality of switching power amplifiers, each phase-shifter being operable to phase-shift the gated pulses into phase-shifted gated pulses responsive to a phase-shifting command signal, wherein the on/off signal received by each switching power amplifier corresponds to the phase-shifted gated pulses from its corresponding phase-shifter.

4. The integrated circuit antenna array of claim 3 , wherein the high-voltage substrate has a first surface facing a first surface of the low-voltage substrate, and wherein the antennas are adjacent a second opposing surface of the high-voltage substrate.

5. The integrated circuit antenna array of claim 4 , wherein the switching power amplifiers are adapted to receive the on/off RF signal through transformers.

6. The integrated circuit antenna array of claim 5 , wherein each transformer has a primary coil formed in metal layers adjacent the first surface of the low-voltage substrate and a secondary coil formed in metal layers adjacent the first surface of the high-voltage substrate.

7. The integrated circuit antenna array of claim 6 , wherein the metal layers adjacent the first surface of the high-voltage substrate have an overlaying passivation layer and a final metal layer deposited on the overlaying passivation layer, and wherein the metal layers adjacent the first surface of the low-voltage substrate have an overlaying passivation layer and a final metal layer deposited on the overlaying passivation layer, the final metal layers being alloyed together to bond the high-voltage substrate to the low-voltage substrate.

8. The integrated circuit antenna array of claim 4 , wherein the switching power amplifiers are adapted to receive the on/off RF signal through ohmic contacts.

9. The integrated circuit antenna array of claim 3 , further comprising at least one controller integrated with the low-voltage substrate, the at least one controller being operable to provide the frequency command, the gating command, and the phase-shifting commands.

10. The integrated circuit antenna array of claim 3 , wherein the VCO includes a varactor having a capacitance that is responsive to the analog voltage.

11. The integrated circuit antenna array of claim 10 , wherein the VCO further includes a pair of cross-coupled amplifiers.

12. The integrated circuit antenna array of claim 1 , wherein each switching power amplifier is a class E switching power amplifier.

13. The integrated circuit antenna array of claim 1 , wherein each switching power amplifier is a class F switching power amplifier.

14. The integrated circuit antenna array of claim 1 , wherein the low-voltage substrate comprises silicon germanium and wherein the high-voltage substrate is selected from the group consisting of gallium arsenide, indium phosphide, and gallium nitride.