Design and Fabrication of 430MHz Unequal Amplitude Hybrid Coupler for T-Radar Beam Forming Unit

Background/Objectives: This letter describes the design simulation and fabrication the design, simulation and fabrication of an P-band frequency band unequal amplitude 90° hybrid coupler. This hybrid coupler is used to design a feeder network with 4 output ports for T-Radar Wind Profiler Operating at 430MHz is achieved with a frequency bandwidth exceeding 50MHz. Methods/Statistical Analysis: The hybrid coupler is designed with the help of conventional microstrip technology. Measured and simulation results has been provided for the components (Equal amplitude hybrid couplers, Unequal amplitude hybrid coupler) used to implement the feeder network. The microstrip hybrid coupler with unequal amplitudes with 90° phase difference is achieved with varying impedances of the one of the arms in a hybrid coupler. Findings: The proposed coupler is easily fabricated on the glass epoxy PCB without any lumped element. There is a good agreement between measured, simulated and theoretical prediction validated the feasible configuration of the proposed coupler and amplitude weights are designed based on array synthesis so called Taylors 1-parameter method for side lobe level -17 dB down from the main beam. A full wave EM simulator zeland IE3D V12.02 and Ansoft designer is used for designing hybrid coupler. Applications/ Improvements: The fabricated coupler is best suited for shared aperture antenna beam forming network and Feeder network using hybrid coupler for 430 MHz Radar applications. To demonstrate our design theory, a practical unequal power hybrid coupler is designed, simulated and fabricated. The measured results shows that the Return losses are larger than 25dB. The power couplings S21 and S31 is -4.38 dB and -3.17 dB and the output phase difference is 88.3180 at the operating frequency.