Varactor-tuned wideband band-pass filter for 5G NR frequency bands n77, n79 and 5G Wi-Fi

Alireza Golestanifar; Gholamreza Karimi; Ali Lalbakhsh

doi:10.1038/s41598-022-20593-x

Varactor-tuned wideband band-pass filter for 5G NR frequency bands n77, n79 and 5G Wi-Fi

Sci Rep. 2022 Sep 29;12(1):16330. doi: 10.1038/s41598-022-20593-x.

Authors

Alireza Golestanifar¹, Gholamreza Karimi², Ali Lalbakhsh^{3

4}

Affiliations

¹ Electrical Engineering Department, Faculty of Electrical and Computer Engineering , Razi University, Kermanshah, Iran, 6714967346.
² Electrical Engineering Department, Faculty of Electrical and Computer Engineering , Razi University, Kermanshah, Iran, 6714967346. ghkarimi@razi.ac.ir.
³ School of Engineering, Macquarie University, Sydney, NSW, Australia.
⁴ School of Electrical and Data Engineering, University of Technology Sydney (UTS), Sydney, NSW 2007, Australia.

Abstract

A wide-band band-pass filter (BPF) using coupled lines, rectangular stubs and Stepped-Impedance Resonators (SIRs) is presented in this paper. The proposed BPF operates over a large pass-band from 3.15 to 6.05 GHz covering 5G New Radio (NR) frequency Bands n77, n79 and 5G Wi-Fi, which includes the G band of US (3.3 to 4.2 GHz), 5G band of Japan (4.4 to 5 GHz) and 5G Wi-Fi (5.15 to 5.85 GHz). The presented filter has a maximum pass-band Insertion-Loss (IL) of 2 dB, a sharp roll-off rate and suppresses all the unwanted harmonics from 4.2 GHz up to 12 GHz with a 15 dB attenuation level. The performance of each section can be analyzed based on lumped-element circuit models. The electrical size of the BPF is 0.258 λ_g × 0.255 λ_g, where λ_g is the guided wavelength at the central frequency. The design accuracy is verified through implementing and testing the final BPF. The pass-band band-width can be controlled by adding the varactor diodes. A good relationship between the band-width and the varactor diodes are extracted by the curve fitting technique.