Broadband Coplanar Waveguide to Air-Filled Rectangular Waveguide Transition

Abstract

This article introduces a novel transition between coplanar waveguide (CPW) and air-filled rectangular waveguide (RWG). A rectangular radiator etched with a semi-elliptic slot is connected to the center conductor of CPW to realize the transition, which broadens the bandwidth. This direct transition does not require intermediate transition or air-bridges. Moreover, the planar circuit of the transition can be designed with high- and low-permittivity materials (εr = 10.2 and 2.22), which offer more benefits in both PCB and MMIC design. Two back-to-back transition prototypes at X-band are designed, fabricated and measured. The 15 dB fractional bandwidths are expanded to 44.7% and 47.6% respectively, which have been demonstrated in both of the transitions (εr = 10.2 and 2.22). The measurement results agree well with simulation results, which validate the feasibility of this design.

Broadband Waveguide-to-Differential-Line Transition in Multi-Layer Substrates With Triple Stacked Patch in 300 GHz Band

“…However, the design frequencies and techniques used in this paper differ from those of the proposed method. For instance, a transition from CPW to airfilled rectangular waveguide was proposed in [31].…”

“…Recently, the types of transitions that have gained recognition are the E-shaped patch element [23], slot coupling technique in multi-layer substrates [24], V-shaped patch element [25], via-less with choke structure transitions [26], [27], rectangular patch with the positioning of the via-hole to control the transmission mode [28], and via fence and air hole matching structures [29], [30]. CPW to airfilled rectangular waveguide transition using a rectangular radiator etched with a semi-elliptic slot [31]. Suspended stripline to air-filled rectangular waveguide transition with a U-shaped patch [32].…”