Design and Analysis of 1:8 Radio Frequency Feeding Network Using Step-Down Impedance Transformer for C-Band Airborne Synthetic Aperture Radar Applications

Abstract

In this research, we developed a unique power divider circuit construction that suppresses harmonic components while providing unequal power division ratios. In antenna arrays, a power divider is used to divide the power among the array's elements. Depending on the design, different power dividers have distinct properties. The purpose of this project was to create a design and examine a 1:8 unequal power divider for C-band applications that operates at 5.3 GHz. The prototype was built on a single board using a duroid RT5880 substrate with relative permittivity of 2.2 and thickness of 1.6 mm. A quarter-wave transformer was utilized to evenly distribute the entire incident power. This design involves adding an extra transmission line to the input side, which is known as a step-down transformer. The input impedance values were reduced and outstanding performance was achieved by using the step-down transformer. Advanced design system software was used in the simulations. The isolation network, which consisted of resisters between the transmission lines, was critical in implementing the radial layout styles and also improved the output port matching and port-to-port isolation. In the operating frequency range, the return loss parameters (S<sub>11</sub>–S<sub>99</sub>) and the isolation were greater than −17 and −37 dB, respectively. The intended structure is compact. The simulated results were in good agreement and demonstrated that all of the ports had matching impedance and the isolation matched the application's requirements.