Gap Waveguides Using a Suspended Strip on a Bed of Nails

Abstract

This letter discusses the feasibility of a new type of waveguide consisting of a strip suspended on a bed of nails. The bed of nails enforces a stopband, while the strip opens a propagating path that can be used to design circuits and feeding networks for the microwave and millimeter-wave bands. Advantages and drawbacks with respect to existing ridge gap waveguide are discussed. Experimental demonstration is also given.Index Terms-Electromagnetic band-gap (EBG) technology, gap waveguide, millimeter-wave technology, quasi-TEM waveguide.

Dielectric Bed of Nails in Gap-Waveguide Technology at Millimeter-Wave Frequencies

“…The power transmission in the designed dielectric bed of nails is done by means of a suspended strip, which was recently proposed to test several circuits on the same bed of nails [6]. This configuration has been simulated with Ansys HFSS [9] considering a finite number of pins in the transverse direction (3 pins on each side of the strip ended in a metallic wall) and periodic boundary conditions in the longitudinal direction (see inset of Fig.…”

“…These advantages allow the design of low-loss transmission lines [4] and circuits with solid ridge [5] or suspended strips [6].…”

“…Gap waveguides may be fed with vertical [4] or longitudinal pins [6]. In case of suspended-strip gap waveguides, a transition from rectangular waveguide to metallic strip has been proposed [7] for measuring prototypes without soldering.…”

Metasurfing since 1987 - a personal story involving soft and hard surfaces, EBG surfaces, cloaking, gap waveguides and mass production

“…They appear in gaps between metal surfaces, and in three main forms depending on how the waves are guided in the gap [14]: ridge gap waveguide [15], groove gap waveguides [16] and microstrip gap waveguides [17]. The latter appears also in a version with via holes in the strip [18], now referred to as a microstrip-ridge gap waveguide.…”

A frequency-dependent equivalence between groove gap waveguide and rectangular waveguide

“…At millimeter wave bands, dielectric materials can have high losses [5]- [6] and coupling to substrate modes [7]- [8] can be problematical. Recently, in an attempt to solve these problems, Gap Waveguide (GW) was proposed [10]- [11]. GW is based on the use of a periodic structure, usually realized by square metal pins, Fig.…”