Capacitively Coupled Bandpass Filter Using Defected Ground Structure Featuring Shield Current Control

• Published in: 2022 19th International Conference on Electrical Engineering, Computing Science and Automatic Control (CCE) pp. 1 - 6
• Main Authors: Aguilar-Torrentera, Jorge, Galvan-Tejada, Giselle M., Ramon Rodriguez-Cruz, Jose
• Format: Conference Proceeding
• Language: English
• Published: IEEE 09.11.2022
• Subjects: Band-pass filters; defected microstrip structure; electromagnetic bandgap component; Magnetic separation; metallic shield; Microstrip filters; microwave bandpass filters; Microwave measurement; Resonator filters; Solid modeling; Transmission line measurements
• ISSN: 2642-3766
• DOI: 10.1109/CCE56709.2022.9975893

In this work, the design of capacitively coupled bandpass filter using a modified defected ground structure is presented. The unit-cell consists of a novel microstrip-type defect etched on the ground plane that retraces the shield current whereby regulating the magnetic current flow around its apertures at high frequencies. The equivalent circuit-model capacitance of such microstrip line makes available filter design having its bandpass frequency shifted to the higher side of the self-resonant frequency of constituent cells. The design approach is illustrated by a filter designed with bandpass at 10 GHz and its bandstop response is compared with that of a filter design with conventional capacitive-gap series resonators. It is seen that etched lattice size can be chosen to develop a specific inductance of the transmission line while keeping an allowable radiation loss. Besides, we analyze the effect of placing a separate solid metal in proximity with the ground plane of the microstrip line to evaluate the effectiveness of blinding moderate field leakage from the unit-cell. Numerical results obtained by three-dimensional electromagnetic simulation allows assessment of the proposed structures.