New Miniaturized Dual-Mode Dual-Band Ring Resonator Bandpass Filter With Microwave C-Sections

Abstract

A new miniaturized dual-mode dual-band ring resonator bandpass filter is implemented by a cascade of several microwave C-sections. Each C-section is used to substitute a transmission line section of designated electrical length. Through proper design of input/output coupling configuration, two transmission zeros can be created on both sides of each passband. Two circuits with four and six microwave C-sections are fabricated for confirmation. They occupy less than 30% of the area of a traditional ring resonator filter. Measured responses agree very well with the simulation.