Methods for Attenuating and Terminating Waves in Ridge Gap Waveguide at W-Band: Carbon-Loaded Foam, Carbonyl Iron Paint, and Nickel Plating

Abstract

Several methods for electromagnetic waves matched termination and attenuation in a ridge gap waveguide (RGW) are experimentally investigated at W-band. At these frequencies, the implementation of matched loads and attenuators is especially complicated due to small sizes of RGW design features that limits application of traditional waveguide absorbing structures (e.g., absorbing sheets and finlines, ferrite insets, carbonyl iron walls, etc.). The following three techniques are considered: (i) filling an RGW gap with a carbon-loaded foam; (ii) covering a ridge (and pins) with a carbonyl iron paint; (iii) selective nickel plating of an RGW line segment. It was found that the first method exhibits a great broadband absorbing performance and can be easily implemented in a lab environment, whereas the second method can realize a more accurate and predictable attenuating performance. Finally, nickel plating allows for designing resonant RGW terminations and is more interesting from the industrial perspective.

A Compact and Wideband MMIC-to-Ridge Gap Waveguide Contactless Transition for Phased Array Antenna Front Ends

“…As seen, the transition 2-port network has the input RGW interface. This reference RGW supports the ridge mode with a cut-off frequency of 72 GHz and has the (80 -160) GHz single-mode operation bandwidth [5], [19], provided by two rows of the pin electromagnetic band gap (EBG) surface. The reference RGW is connected through a 2-step RGW impedance transformer, comprised of two RGW transmission line (TL) segments T L m1,2 , to the coupling region interfacing with an MMIC.…”

Wideband Open-Ended Ridge Gap Waveguide Antenna Elements for 1-D and 2-D Wide-Angle Scanning Phased Arrays at 100 GHz

“…In all simulations, the 0.5-µm Groisse surface roughness model is used. A detailed characterization of this RGW can be found in [20].…”

“…5(a)], while all neighboring elements were terminated with matched loads. The loads were made of carbon-loaded absorbing foam (ABS) WAVASORB FS from Emerson & Cuming [20].…”

Millimeter-Wave Quasi-Optical Feeds for Linear Array Antennas in Gap Waveguide Technology

“…A single-mode operation bandwidth of the basic RGW spans 80-160 GHz. A dispersion diagram and losses analysis for this RGW can be found in [11]. Thus, the QO feed comprises three main parts: (i) the input basic RGW with a transition to the GGW input; (ii) the linearly tapering or radial GGW; (iii) the array of the output RGWs with transitions to the radial GGW output.…”