Application of Compact Folded-Arms Square Open-Loop Resonator to Bandpass Filter Design

Area of Science:

• Electrical Engineering
• Electromagnetics
• Microwave Engineering

Background:

• Conventional microstrip square open-loop resonators (SOLR) face limitations in device size.
• Miniaturization is crucial for modern electronic applications.

Purpose of the Study:

• To introduce and validate the folded-arms square open-loop resonator (FASOLR) as a compact alternative to SOLR.
• To demonstrate the effectiveness of FASOLR by designing and testing a five-pole Chebyshev bandpass filter (BPF).

Main Methods:

• Implementation of a five-pole Chebyshev bandpass filter utilizing the compact FASOLR design.
• Fabrication and characterization of the BPF on a Rogers RT/Duroid 6010LM substrate.
• Comparison of simulated and measured electromagnetic (EM) performance parameters.

Main Results:

• The designed BPF operates at a center frequency of 2.2 GHz with a 10% fractional bandwidth.
• Simulated results show a minimum insertion loss of 0.8 dB and return loss of 22.6 dB.
• Measured results confirm a minimum insertion loss of 0.9 dB and return loss better than 19.2 dB, validating the design.

Conclusions:

• The FASOLR enables significant device size miniaturization compared to conventional SOLR.
• The implemented Chebyshev BPF demonstrates high performance, validating the utility of FASOLR for compact filter designs.
• Experimental results closely match EM simulations, confirming the accuracy of the design methodology.