Millimeter-Wave Passive Components and Six-Port Network Analyzer in Dielectric Waveguide

The nonradiative dielectric waveguide (NRD guide) is suitable for constructing millimeter‐wave circuits of complicated structure because of nonexistence of radiating wave at the bend and discontinuity based on the non‐radiative nature, the construction technique of the T‐junctions, the cascaded multiport junctions in NRD guide, and their performances at 50 GHz are described in this paper. First, a new T‐junction based on the mode transformation between the two types of nonradiative modes in the NRD guide is proposed and its operation is confirmed experimentally. Next, using this T‐junction, a three‐port and a five‐port junction have been fabricated and tested. Reasonable output levels of ‐3 dB and ‐6 dB in average for the three‐port and five‐port junctions were obtained, respectively, over a bandwidth of about 2 GHz with the center frequency at 50 GHz. From this fact, it is evident that the radiation loss which cannot be suppressed in conventional dielectric waveguide junctions can be completely eliminated in the NRD‐guide junctions. The output ports of these junctions can be increased by stacking several T‐junctions. These junctions can be applied for feed network of millimeter‐wave planar antenna in the future.

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