Direct antenna modulation: analysis, design, and experiment

In this paper, a symmetrical 1.5 GHz patch antenna has been designed, constructed, simulated and experimentally fine-tuned to be the radiating element in the experiment to implement direct antenna modulation. With a resonant bandwidth of about 30 MHz (using a 10 dB or better return-loss standard), there is significant room for improvement that direct antenna modulation can offer to the information bandwidth of the system. By driving the antenna at resonance and directly modulating it with an integrated Schottky diode being biased by an external pulse train, the frequency of this external modulating signal is predicted to far exceed the resonant bandwidth of the antenna and still produce a clear demodulated waveform at the receiving end of a basic communication system