A Unified Architecture for Integrated Circuit and Radiation Function Using Co-Located Active Device and Multimode Antenna

This article proposes a simple and efficient unified and integrated circuit antenna (UNICA) approach for achieving simultaneous front-end active circuitry and radiation functions in a unified design framework. This is accomplished by directly integrating the active device at optimal physical locations for required impedance matching in the multimode operation of the antenna. A systematic analysis of mode behavior, design flexibility, and radiation performance for various microstrip antennas is conducted. From this analysis, the rectangular patch antenna (RPA), operating in orthogonal modes, was selected as the most suitable radiator due to its ability to meet the desired performance criteria. The orthogonal mode operation of the RPA provides two isolated regions for the direct integration of the active device, allowing independent control over the corresponding impedance-matching condition at each terminal. A general modeling procedure for this unified solution is presented, followed by prototype demonstrations, including a class-A amplifier-antenna prototype operating at a resonant frequency of 5 GHz. Experimental results show that the prototype achieves an impedance-matched condition and delivers an amplification gain of 13 dB compared to its passive counterpart. These findings highlight the potential of this UNICA approach for efficient integration of amplification and radiation functions in a compact design.