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Small scale lowpass and quad-band bandpass filter for 5G application
Dilip Kumar Choudhary1, Kushagra Pratap2
1School of Electronics Engineering, Vellore Institute of Technology, Vellore, 632014, India. dilip.choudhary6@gmail.com.
Scientific Reports
|November 25, 2025
Summary
A novel compact filter integrates a shorted interdigital capacitor (IDC) and resonators for low insertion loss and high selectivity. This quad-band passband filter is validated experimentally and suitable for 5G communication frequency range-1 (FR1).
Area of Science:
- Electrical Engineering
- Electromagnetics
- Microwave Engineering
Background:
- Achieving compact, high-performance filters with multiple passbands is crucial for modern wireless communication systems.
- Existing filter designs often face trade-offs between size, insertion loss, selectivity, and bandwidth coverage.
Purpose of the Study:
- To design and validate a novel, small-scaled lowpass and quad-band passband filter.
- To achieve low insertion loss, high selectivity, and wide bandwidth coverage for 5G applications.
Main Methods:
- Integration of a shorted interdigital capacitor (IDC), closed ring resonator, meander line, and virtual ground plane.
- Utilizing pairs of meander lines and rectangular stubs to construct quad bandpass and lowpass filter characteristics.
- Experimental validation through measurements correlating with simulated results.
Main Results:
- The proposed filter occupies a compact area of 15.6 mm × 24.6 mm.
- Achieved low insertion loss and high selectivity across multiple frequency bands.
- Demonstrated fractional bandwidths of 63.76%, 22.55%, 17.15%, and 4.3% in the four passband zones.
- Resonance frequencies are adjustable by altering structural parameters.
Conclusions:
- The designed filter meets the requirements for 5G communication frequency range-1 (FR1), covering the 0.45-6.0 GHz bands.
- The integration of specific components leads to enhanced impedance matching and transmission properties.
- The filter's design is validated, showing its practical applicability for advanced wireless systems.
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