A Compact Balanced Phase Shifter With Wideband Common-Mode Suppression

Abstract

In this paper, a balanced phase shifter using cascaded three microstirp lines and two coupled lines is proposed. The reference line is fixed without center delay line. With such configuration, wideband differential-mode (DM) phase shift can be achieved. The coupled line and half-wavelength microstrip line provide the out-of-band and in-band common-mode (CM) suppression, respectively. Compared with the state-of-the-art balanced phase shifters, the proposed balanced phase shifter has the advantages of wideband CM suppression and compact size with simple structure and fixed reference line. Theoretic analysis, parametric study and design procedure are carried out completely. To verify the theoretic prediction, two prototypes covering the frequency of 1.8 GHz are designed with the relative operating bandwidth for 45 • ± 2.1 • (90 • ± 3.7 •) phase shifter of 50% (53%), with the minimum return loss better than 14.7 dB, and the relative CM suppression bandwidth better than 150%.

A Compact Single-Layer Balanced Phase Shifter With Wide Bandwidth and Uniform Reference Line

“…The operating bandwidth covering DM and CM performances of the proposed design is increased to 81% with the circuit size of 0.35 λ 2 g . Comparing with our previous design [22], the symmetric structure, the independent control of DM and CM response, and the position of the delay line make the proposed design show wider operating bandwidth and smaller maximum insertion loss. The odd-even-mode analysis is used to predict DM and CM responses.…”

“…Furthermore, compared with the balanced design in [20], the proposed design has simpler structure because of the single-layer substrate and uniform reference line. Compared with the singlelayer balanced design in [22], the proposed design shows lower maximum insertion loss. Compared with the singlelayer balanced designs in [19], [21], [23], the proposed one has more compact size.…”

“…It is important to note that the reference line in [20], [21] is not uniform for different phase shifts. In [22], a balanced phase shifter using asymmetric method is introduced with much wider CM suppression bandwidth. To further improve the operating bandwidth, the balanced phase shifter with the operating bandwidth of 68.5% is realized on single-layer substrate with uniform reference line [23], but the multi-order structure results in large size of 0.93λ 2 g .…”

Simple ladder‐like single‐layer balanced wideband phase shifter with wide phase shift range and appropriate common‐mode suppression

“…single-ended) phase shifters. However, the single-ended structures are more common due to the reduced printed circuit board size and cost and in contrast very limited papers on balanced phase shifters have been reported in the literature so far [29][30][31][32][33].…”

“…However, the DM phase shift bandwidth is relatively low. In [32], a compact one-layer balanced phase shifter is suggested that utilises a fixed reference line topology for all desired phase shifts. This structure surprisingly does not require any symmetric line, while achieves a good CM suppression bandwidth.…”