Dual-frequency operation of active concentric circular ring microstrip antenna

Dual-frequency operation of microstrip antennas have been studied to some extent by many researchers. Until now, however, there have been little attention to the integration these type of microstrip antennas with active circuits to perform what we call dual-frequency operation, although this integration is already known to increase the performance of the microstrip antenna. This paper describes the design and construction of a dual-frequency operation active microstrip antenna that includes the integration of circular ring concentric patch microstrip antenna with a microwave oscillator and amplifier