Direct downconversion active antennas for modulation and demodulation

In this paper, two active antennas with modulation and demodulation functions are introduced. A patch antenna integrated with two Schottky diodes is implemented to fulfil single sideband modulation and I&Q demodulation. A variation of this configuration can carry out double sideband modulation with carrier suppression and homodyne detection. Moreover, some parameters of the active antennas, such as conversion loss and radiation pattern are measured. The active antennas have potential use for direct-conversion radio transceivers in digital communication