A new micro-machined millimeter-wave and terahertz snap-together rectangular waveguide technology

Abstract

A novel technique for micro-machining millimeter and submillimeter-wave rectangular waveguide components is reported. These are fabricated in two halves which simply snap together, utilizing locating pins and holes, and are physically robust, and cheap, and easy to manufacture. In addition, S S Sparameter measurements on these structures are reported for the first time and display lower loss than previously reported micro-machined rectangular waveguides.

Micromachined 3D millimeter-wave and terahertz devices

“…Among them, UV-LIGA [1], PolyStrata TM [2], Silicon-DRIE [3] and thickresist photolithography [4], [5] are the most promising in providing the desired fabrication accuracy for up to 1 THz. LIGA is able to produce all-metal solid structures.…”

Millimeter Wave Substrate Integrated Waveguide Antennas: Design and Fabrication Analysis

“…McGrath et al [4] formed an air-filled waveguide channel in silicon, and reported measured losses of around 0.02 dB/mm at 100 GHz. In [5], Digby et al, used a different micro-machining process to form a substrate integrated 100 GHz air-filled waveguide. Their measured data, around 0.05 dB/mm at 100 GHz was slightly higher than that of McGrath, but it was suggested by the authors that the high attenuation might have been due to some of the waveguide walls being only one skin depth thick.…”

Analysis and design of efficient passive components for the millimeter-wave and THz bands

“…First serious attempts to design THz RWGs came around the year 2000 [192], [337], [338], when several research groups, pioneers in mm-wave, not so technologically mature as these days, started to venture in the sub-mm wave regime, even properly naming these RWG as THz waveguides. From this starting point, either due to manufacturing limitations [339], [338], or inherent structure losses and performance [192], it has been quite common to introduce some modifications on the usual RWG (structure, dimensions and/or modal operation).…”

“…One reason for the first one is that, although at THz frequencies the penetration depth is lower, some new manufacturing techniques are based on thin metal layers that may not reach the penetration depth. The other reason is that wall roughness may be comparable the penetration depth [337], [349]- [353]. The second one arises because assumed metal model properties (very high σ or perfect conduction) may noticeably change due to manufactured surface roughness [354], [342], or microscopic electromagnetic interaction (Drude model of metals [347]) [355]- [348].…”

“…In the pioneer works [337], [338] manufacturing was done through that time lithographic micromachining, with the important drawback of having maximum manufacturable heights, being the ratio b = a/2 not satisfied by far. In [337], a 2.54 mm x 0.7 mm gold sputtered RWG exhibited 0.2 dB/mm at 0.1 THz, much more than the expected value, although overcoming by far previous works. Augmented attenuation was mainly attributed to bad metal contact due to metal roughness in this H-plane manufactured RWG.…”