Novel balanced single/dual‐band bandpass filters based on a circular patch resonator

Abstract

A new strategy for designing single‐band and dual‐band balanced bandpass filters (BPFs) based on a circular patch resonator is proposed in this study. By altering the output balanced ports of the balanced BPFs to inhibit or transport the TM31 mode of the circular patch resonator under the differential‐mode (DM) excitation, a single‐band or dual‐band balanced BPF can be realized. As the odd modes could be restrained under the common‐mode (CM) excitation, the balanced BPFs could feature high CM suppression in the DM passbands. Meanwhile, several perturbing tactics are introduced to improve the performance of the balanced BPFs. Specifically, perturbation vias are presented to disturb the electric field distribution to enhance the CM suppression in the DM passbands, and slots are applied on the circular patch resonators to perturb the current distribution to amend the second DM passband of the dual‐band balanced BPF. The proposed single‐band and dual‐band balanced BPFs are fabricated and characterized. Good agreement can be achieved between the simulated and measured results of the fabricated balanced BPFs, which validates the feasibility of the proposed design method.

Broadband Balanced-to-Balanced Filtering Power Divider Using HMSIW-SSPP Transmission Line

“…Table 3 shows the performance of the proposed BTB FPD and other reported BTB FPDs. The proposed BTB FPD based on the HMSIW-SSPP transmission line has a broader operating bandwidth than the BTB FPDs in [ 2 , 3 , 4 , 6 , 7 , 8 , 9 ], and it also possesses independent control of the passband’s lower and upper cut-off frequencies, making obtaining the desired frequency response easier. Although the SSPP BTB FPD in [ 5 ] achieves a 152% FBW and compactness, this proposed design has better IL, RL, and isolation than that of [ 5 ].…”

“…The proposed BTB FPD’s DM isolation between output ports approaches the BTB FPDs in [ 8 , 9 ], but within a broader range. This design features a better IL than that of BTB FPDs in [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ].…”

“…The proposed BTB FPD's DM isolation between output ports approaches the BTB FPDs in [8,9], but within a broader range. This design features a better IL than that of BTB FPDs in [2][3][4][5][6][7][8][9]. Table 3 shows the performance of the proposed BTB FPD and other reported BTB FPDs.…”

“…This makes it a crucial passive device for RF/microwave circuits. Previous studies have proposed BTB FPDs based on microstrip resonators [ 1 , 2 ] and patch resonators [ 3 , 4 ], showing good performance in common-mode (CM) suppression and featuring a straightforward design. However, these designs suffer from limitations in power capacity and increased losses at higher frequencies.…”

Four Subbands from Dual Mismatched Wideband Bandpass Filter for 5G/WAS/Wi-Fi/WiMAX/WLAN Applications

“…Another new approach used nowadays is the defected ground structure (DGS) [28] or/ and defected stub [29] technique. It finds several shapes, among them circular resonators [30]. Metamaterials are becoming an up-and-coming option, especially with high frequencies [31][32][33].…”