A Balanced Substrate Integrated Waveguide Phase Shifter with Wideband Common-Mode Suppression

In this paper, a slotted substrate integrated waveguide (SIW) is used to create a balanced phase shifter with wideband common-mode (CM) suppression. Differential-mode (DM) impedance matching and CM suppression are achieved by utilizing the fact that TE20 mode and TE10 (TE30) mode can only transmit DM signals and CM signals, respectively, and by increasing the bandwidth for CM suppression via slots. Furthermore, a wideband phase shift with low phase deviation can be obtained due to the phase slop counteract between the slot and the delay line. Compared with the state-of-the-art, the proposed one has the advantages of wideband CM suppression, wide phase shift range, and a simple and easy-to-make structure. Five prototypes covering the frequency of 3.5 GHz are designed with the relative operating bandwidth for 45 degrees +/- 2 degrees (90 degrees +/- 4.5 degrees, 135 degrees +/- 6 degrees, and 180 degrees +/- 8 degrees) phase shifter of 20% (20%, 20%, and 20%), with the minimum insertion loss of 0.41 dB (0.5 dB, 0.58 dB, and 0.59 dB), with the minimum return loss greater than 15 dB, and with the relative bandwidth for 15-dB CM suppression of 59% (59%, 58%, and 57%).

Automated summary

This paper proposes a slotted substrate integrated waveguide (SIW) to achieve a wideband common-mode (CM) suppression phase shifter. Differential-mode (DM) impedance matching and CM suppression are realized by utilizing the characteristics of TE20 mode and TE10 (TE30) mode. Wideband phase shift and low phase deviation are achieved through the counteraction of the slot and the delay line. Compared to existing technologies, the proposed method offers advantages in terms of wideband CM suppression, wide phase shift range, and simple structure. Five prototypes are designed with different frequency ranges and achieve satisfactory performance in terms of insertion loss, return loss, and CM suppression bandwidth.