Comparison Of Π Shape and T Shape Junction Mikrostrip 3db For Coastal Radar Application

Abstract

The 3 dB or Quadrature (90-degree) hybrid coupler 3 dB has an important role in various RF systems such 
as transmitters, receivers, matrix Butlers, signal processing circuits, data communications, phase shift, 
power coupling and power beam sampling applications. The standard hybrid coupler basically has 
drawbacks, including having limited band characteristics where the impedance bandwidth is 10% and 
has a large size or dimension. This 3 dB coupler is generally used stand-alone and connected to other 
components using RF cables. Besides, it is also used in conjunction with other microwave circuits such as 
amplifiers, mixers, and power dividers. To determine the overall system performance, it is necessary to 
design and simulate the coupler device. works at a working frequency of 3 GHz using Glass Epoxy (FR4) 
substrate. which has a dielectric constant of 4.3 with a thickness of 1.3 mm. The design was carried out 
with the help of the CST 2020 simulation software. In this study, a comparison of the 3db microstrip isolation 
values was carried out which had different shapes, namely the J shape and the t shape junction. where 
both have an output of -3dB and a phase difference of 90°.