Differential‐to‐single‐ended crossover based on dumbbell‐shaped defected ground resonators for dual‐band applications

Abstract

This article presents a novel differential-to-single-ended (DS) crossover by using two rings included of controllable frequency ratio of composite rightand left-handed (CRLH) transmission lines for dual-band applications. To reject the out-of-band differential-mode transmission coefficient, two dumbbell-shaped defected ground resonators (DGRs) are utilized over the differential transmission lines. Theoretical analysis proves that the frequency ratio can be controlled by choosing the number of designing CRLH cells and the parameter values appropriately. Also, desired electrical lengths and impedances of DGRs were obtained at the bandstop notch of differential-mode transmission coefficient by conducting common-and differential-mode analysis of lumped element equivalent circuit. To validate the proposed structure, two fabricated prototypes including the DS crossover designing at 1.8 and 4.2 GHz and separate differential lines with embedded DGRs were fabricated and measured. Measurement mixed-mode results exhibit that the fabricated crossover has great results at both frequency bands and has a good out-of-band differential insertion loss rejection.

Design of Frequency-Reconfigurable Branch-Line Crossover Using Rectangular Dielectric Channels

“…Table 5 shows a comparative study to demonstrate the superiority of the proposed reconfigurable crossover over the previously reported crossovers. Compared to [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] and [38][39], the proposed crossover exhibits minimal insertion loss throughout the tuning range. When compared to [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] and [38][39], the proposed crossover achieves excellent fractional bandwidth, isolation, and return loss.…”

“…Compared to [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] and [38][39], the proposed crossover exhibits minimal insertion loss throughout the tuning range. When compared to [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] and [38][39], the proposed crossover achieves excellent fractional bandwidth, isolation, and return loss. In addition, while the proposed work and earlier works in [38][39] show frequency tunable crossovers, the crossovers reported in [6][7][8][9][10][11][12][13][14][15][16]…”

“…These designs exhibited high return loss in the passband in addition to fabrication problems. To address these issues, branch line structures have been proposed to realize planar crossovers with smaller footprint areas, wideband, and multi-band responses [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22].…”

“…To support multiple standards in current wireless technology, several configurations have been developed to implement multi-band crossovers [15][16][17][18][19][20][21][22]. In [15], a dualband crossover has been designed by employing right/lefthanded transmission lines.…”

“…In [18], a planar dual-band crossover with high isolation has been constructed using open-ended coupled lines. In [19], a dual-band crossover has been designed by using a dumbbell-shaped resonator. In [20], a triple-band planar crossover has been realized based on the multi-band transmission lines.…”