A Dual-Band Bandpass Filter with Wide Upper Stopband Using Stepped-Impedance Resonators and an Integrated Low-Pass...

Area of Science:

• Electrical Engineering
• Electromagnetics
• Microwave Engineering

Background:

• Wireless communication systems require efficient filtering to manage multiple frequency bands and mitigate interference.
• Existing filters often struggle to provide both dual-band operation and wide stopband suppression, leading to signal degradation.
• Stepped-impedance resonators (SIRs) offer a flexible approach to designing compact and high-performance microwave filters.

Purpose of the Study:

• To propose and design a novel dual-band bandpass filter with an extended upper stopband.
• To achieve targeted operating frequencies of 2.5 GHz and 5.35 GHz suitable for common wireless applications.
• To minimize insertion loss within the passbands for efficient signal transmission.

Main Methods:

• Integration of stepped-impedance resonators (SIRs) with a low-pass filter topology.
• Design and simulation of the filter structure to meet specific frequency response requirements.
• Validation of the design through comparison of simulation and measured results.

Main Results:

• The designed dual-band filter successfully operates at 2.5 GHz and 5.35 GHz.
• A wide upper stopband from 6.1 GHz to 25 GHz was achieved, effectively suppressing out-of-band signals.
• Low insertion losses of 0.12 dB at 2.5 GHz and 0.6 dB at 5.35 GHz were observed.
• Simulation results closely matched the measured performance, confirming the design's validity.

Conclusions:

• The proposed dual-band bandpass filter effectively meets the requirements for typical wireless communication scenarios.
• The integration of SIRs and a low-pass filter provides a viable method for achieving wide upper stopbands and dual-band operation.
• The filter's performance, characterized by low insertion loss and effective stopband suppression, demonstrates its suitability for practical applications.