Highly Selective Uwb Bandpass Filter With Multi-Notch Characteristics Using Comb Shaped Resonator

Abstract

This paper aims to present a highly selective, compact size new ultra-wideband (UWB) bandpass filter with three sharp notches for UWB indoor applications. The fundamental geometry of the filter is based on a modified multi-mode resonator (MMR) structure which comprises an open-ended step impedance resonator (SIR) attached to an interdigitated uniform impedance resonator (UIR). Realizing a Comb-shaped resonator structure below the UIR and symmetrically extending the lower arm edge of the interdigital coupled lines, three notches are generated at 6 GHz, 6.53 GHz, and 8.35 GHz. These notches have improved the UWB bandpass filter responses by suppressing the existing interferences in the UWB passband created by Wi-Fi 6E (6 GHz), super-extended C band (6.425 GHz ∼ 6.725 GHz), X band satellite communications for satellite TV networks or raw satellite feeds (7.25 GHz ∼ 8.395 GHz). Concurrently the notched band filter has achieved superiority in other salient features concerning passband and stopband of the filter such as a high passband fractional bandwidth (115.76%), low return loss (−13.27 dB), low insertion loss (0.44 dB ∼ 0.97 dB), wide upper stopband (5.37 GHz), nearly flat group delay (0.28 ns ∼ 0.45 ns), etc. The ultimate design of the UWB bandpass filter is fabricated and verified by comparing the simulated filter responses with the measured results indicating a good agreement.

UWB‐BPF based on broadside coupled technology with triple‐notched passband

“…Our triple band notched BPF is compared to examples found in recent literature and shown in Table 1. It is clear that the suggested structure contains two TZs at the passband edges, in contrast to, 2,3,[7][8][9][10][11][12]17 which lacks TZs at both passband edges, 12,13,15,16,19 which has a TZ at only one passband edge. The suggested structure is physically smaller than all, with the exception of Sazid and Raghava, 4 and electrically it is smaller than [1][2][3]5,10,12,13,15,16,19 and comparable to the rest (when all three triple-notch BPFs are evaluated at their central working frequencies).…”

“…It is clear that the suggested structure contains two TZs at the passband edges, in contrast to, 2,3,[7][8][9][10][11][12]17 which lacks TZs at both passband edges, 12,13,15,16,19 which has a TZ at only one passband edge. The suggested structure is physically smaller than all, with the exception of Sazid and Raghava, 4 and electrically it is smaller than [1][2][3]5,10,12,13,15,16,19 and comparable to the rest (when all three triple-notch BPFs are evaluated at their central working frequencies). It is also important to note that the suggested BPF has a simplified geometry, in contrast to, [5][6][7][8][9][10]12 which features vias, [1][2][3]6,[9][10][11][12][13][14] which has fabrication issues because of minimal resonators/slots dimensions.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] Using the transmission zero (TZ) generation technique, these triple passband notches were introduced using defected microstrip structures, 1 defected ground structures (DGS), [2][3][4] wave cancellation, 5,6 triple-mode step loaded resonators, [7][8][9][10][11][12] and other resonators. [13][14][15][16] Other UWB-BPFs produced triple passband notches by combining the aforementioned processes in different ways. [17][18][19] Triple notches were produced via a dual mode SIR with asymmetric coupling (wave cancellation).…”

“…[17][18][19] Triple notches were produced via a dual mode SIR with asymmetric coupling (wave cancellation). 17 While dual multimode resonator (MMR) and complimentary split ring resonator (CSRR) together with DGS and folding MMR produced triple notches in Chiang et al, 18 CSRR with MMR provided triple notches in Borazjani et al 19 These described notched structures did, however, have some obvious flaws, such as improper TZs at either/both passband edges, 2,3,7-11,17/12,13,15,16,19 intricate designs due to the existence of vias [6][7][8][9][10][11][12][13] or design restrictions, 1,3,[5][6][7][11][12][13][14][15][16] and big physical/electrical sizes. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] We present a triple passband notched UWB-BPF (Figure 1) that was created using broad...…”

“…UWB bandpass filter (BPF) with embedded multiple notched passband characteristics were created to get beyond these sources' interference with the performance of UWB systems 1–14 . Using the transmission zero (TZ) generation technique, these triple passband notches were introduced using defected microstrip structures, 1 defected ground structures (DGS), 2–4 wave cancellation, 5,6 triple‐mode step loaded resonators, 7–12 and other resonators 13–16 . Other UWB‐BPFs produced triple passband notches by combining the aforementioned processes in different ways 17–19 .…”