DESIGN OF A CIRCULARLY POLARIZED OSCILLATOR- TYPE ACTIVE INTEGRATED RING SLOT ANTENNA

Abstract

Due to the advancements of the MIC and MMIC technologies, the research in the field of active integrated antennas has been grown for last two decades. In this dissertation, an active integrated antenna that integrates an oscillator and a square ring slot antenna on the same substrate has been designed, simulated and fabricated. The oscillator is designed schematically in the Advanced Design System software. By performing the Harmonic Balance simulation for this oscillator, it gives the frequency of oscillation at 2.4 GHz, with an output power of 8.108 dBm at an emitter bias of -0.824V, with a phase noise of -74.09 dBc/Hz at an offset of 10 KHz from the carrier. The square ring slot antenna is designed in ADS Momentum. This antenna has minimum return loss at 2.4 GHz, and gives circular polarization at 2.57 GHz. This antenna gives an axial ratio below 3 dB at CP center frequency of 2.57 GHz. The simulated radiation patterns of this antenna shows that the cross polarization levels are at least -10 dB lower than those of co polarization for all directions. A prototype of this oscillator type active integrated antenna was fabricated in the laboratory using wet etching techniques, and the measured results for this antenna have been done in an anechoic chamber. To get more output power from the solid state devices at higher frequencies, the power combining techniques are used by combining the output power radiated from the array of the oscillator type active integrated antennas in the free space. The further work related to design of array of oscillator type AIAs, to give circular polarization. The dissertation focuses on the design of a circularly polarized oscillator type active integrated antenna.