Variable High Precision Wide D-Band Phase Shifter

Zhongxia Simon He,Jinlin Liu,Cheng Jin,Sining An

doi:10.1109/access.2020.3012596

Abstract

This paper proposes a new concept of designing compact high precision millimeter-wave wideband variable phase shifters. The phase shifter is implemented with a stacked shim with extremely short length of 0.9 mm and two waveguide flange adaptors with length of 0.5 mm. High precision phase shifting is achieved over entire D-band (110-170 GHz) by rotating the shim 90 degrees from aligned to perpendicular with consistent impedance matching performance. In addition, a glide-symmetric holey electromagnetic bandgap (EBG) structure is adopted to avoid wave leakage from the gap between the shim and the flange adaptors. A proof-of-concept (PoC) demonstrator is designed, manufactured, and tested. The measured results show that the designed stacked shim phase shifter with embedded EBG structure ensures return loss higher than 10 dB across 110-170 GHz with a 75 mu m airgap between waveguide flanges. The studied phase shifter provides a 0.88ffi phase shifting with each degree of mechanical rotation. The fabricated PoC phase shifter has a worst-case insertion loss of 0.92 dB and a return loss of 20 dB across the entire 110-170 GHz band and a maximum phase shift of 30 degrees. At 10 degrees phase shifting, the measured insertion loss is lower than 0.52 dB, and return loss is higher than 23 dB, respectively.

Highlights

Nowadays, cost-sensitive industries such as telecommunication, autonomous vehicles, security imaging have started investigating systems working on frequencies in D-band from 110 to 170 GHz to achieve higher data rate or higher resolution performances
The operation frequency is approaching half fMAX value of most commercial semiconductor processes in D-band frequencies, where fMAX is the frequency at which the transistor’s power gain is equal to one
New transmission line technology in D-band frequencies with low loss and low cost is a key point to be studied for commercializing millimeter-wave applications

Summary

INTRODUCTION

Cost-sensitive industries such as telecommunication, autonomous vehicles, security imaging have started investigating systems working on frequencies in D-band from 110 to 170 GHz to achieve higher data rate or higher resolution performances. In this circumstance, the group delay property is important for such phase shifter to avoid introducing dispersion to the wideband modulated signal. MEMS technology is used to implement phase shifter by switching different open/short stub sections in order to apply phase shifting, as shown in Fig. 2(b) [3] Another phase shifter based on waveguide rotation is introduced in [12].

TWISTED WAVEGUIDE PHASE SHIFTER DESIGN

CONCLUSION