Variable High Precision Wide D-Band Phase Shifter

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 0.5mm. 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 µm airgap between waveguide flanges. The studied phase shifter provides a 0.88º 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 30º. At 10º phase shifting, the measured insertion loss is lower than 0.52 dB, and return loss is higher than 23 dB, respectively.

On the Benefits of Glide Symmetries for Microwave Devices

“…Therefore, the use of periodic structures, such as metallic pins, was proposed in the literature [83]. Similar to metallic pins, glide-symmetric holes can also be used to reduce the leakage [64], [84]. Fig.…”

Dispersion Analysis of Periodically Loaded Transmission Lines with Twist Symmetry Using the Mode-Matching Technique

“…Furthermore, while the stop-band between the first two modes is suppressed in glide-symmetric structures, a large stop-band exists at higher frequency [23][24][25]. This stop-band has been used to design low-cost gap waveguides [26] and filters [27] and to reduce the leakage between waveguide flanges [28,29]. These attractive properties have inspired the development of several semi-analytical methods for the analysis of glide-symmetric structures using circuit models [25,30,31], mode-matching [32][33][34][35], or the multimode transfer-matrix approach [36][37][38].…”

Two-Dimensional Glide-Symmetric Dielectric Structures for Planar Graded-Index Lens Antennas

“…For example, it has been demonstrated that glide symmetry broadens the bandwidth of the electromagnetic band gaps (EBGs) in holey periodic structures [6]. This property has been applied to produce cost-effective gap-waveguide components [7], [8], flanges with low-leakage [9], [10], and filters [11]. Glide symmetry also increases the level of anisotropy of periodic structures [12], [13], which can be used, for example, to compress the size of lenses with transformation optics [14], [15].…”