Silicon micromachined K-band filters
21 Mar 2012-pp 354-357
TL;DR: In this paper, a substrate integrated waveguide (SIW) based filter at K band frequency on silicon substrate is described, where TMAH etching is used to form the via-holes for SIW cavities.
Abstract: This paper describes a substrate integrated waveguide (SIW) based filter at K band frequency on silicon substrate. TMAH etching is used to form the via-holes for SIW cavities. Simulations and comparison of TMAH and Deep reactive ion etching (DRIE) etched cavity has been presented. A micro- machined filter is made from rectangular cavities integrated into a silicon substrate and is fed by coplanar waveguide (CPW) transmission-lines through current probes. Simulated filter using TMAH etching shows insertion loss of 0.29dB and return loss of 21.96 dB.
Citations
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TL;DR: In this article, a robust and tuneless micromachined waveguide diplexer operating in the frequency range 71-86 GHz is presented, which consists of two filters combined to a common waveguide port via an E-plane T-junction.
Abstract: A robust and tuneless micromachined waveguide diplexer operating in the frequency range 71–86 GHz is here presented. The diplexer is based on multiple coupled cavities and it is manufactured using micromachining technology on two staked silicon layers. The diplexer consists of two filters combined to a common waveguide port via an E-plane T-junction. The two eight-order band-pass filters are centered at 73.5 and 83.5 GHz. The fractional bandwidths for two bands are 8.8 and 7.8% at higher- and lower-band, respectively. The measured insertion loss is below 0.7 dB for both the filters and the diplexer isolation is better than 55 dB, as required. The proposed technology allows for a very compact device (<20 × 20 × 1.5 mm) and the first prototypes were proved to be very robust to manufacturing tolerances and environmental tests, thus leading to an excellent tuneless manufacturing yield in future production. The diplexer will be employed in next generation terrestrial radio-link communications front-ends.
8 citations
02 Jun 2013
TL;DR: In this article, a new concept for compact and low-loss Ka-band micromachined bandpass filters for next generation on-board communications is presented which combines micromACHined cavities with multilayer technology on silicon.
Abstract: A new concept for compact and low-loss Ka-band micromachined bandpass filters for next generation on-board communications is presented which combines micromachined cavities with multilayer technology on silicon. The resonator consists of a gold-plated micromachined shielding cavity with a longitudinal 20 μm thick gold-plated silicon membrane. The membrane is short-circuited at both anchored ends and it operates as a λ/2 TEM line resonator. The footprint of a single resonator is reduced by more than 50% with respect to conventional micromachined cavities using the TE101 resonant mode. The measurements of single transmission-type resonators are in very good agreement with the full-wave simulations, demonstrating a high filter robustness to process tolerance. The expected unloaded Q of the resonators for 500 μm thick layers is 600, and the measured value is above 500. Qs above 1000 are feasible with the available technology by simply increasing the number and the thickness of the silicon layers. A 4th order pseudo-elliptic filter at 30 GHz (FBW = 1.7%) has been designed and is under fabrication.
6 citations
References
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01 Aug 1998
TL;DR: In this article, the available etching methods fall into three categories in terms of the state of the etchant: wet, vapor, and plasma, and they are reviewed and compared by comparing the results, cost, complexity, process compatibility, and other factors.
Abstract: Bulk silicon etching techniques, used to selectively remove silicon from substrates, have been broadly applied in the fabrication of micromachined sensors, actuators, and structures. Despite the more recent emergence of higher resolution, surface-micromachining approaches, the majority of currently shipping silicon sensors are made using bulk etching. Particularly in light of newly introduced dry etching methods compatible with complementary metal-oxide-semiconductors, it is unlikely that bulk micromachining will decrease in popularity in the near future. The available etching methods fall into three categories in terms of the state of the etchant: wet, vapor, and plasma. For each category, the available processes are reviewed and compared in terms of etch results, cost, complexity, process compatibility, and a number of other factors. In addition, several example micromachined structures are presented.
780 citations
TL;DR: In this article, high-performance planar micromachined filters at 37 and 60 GHz are presented, which consist of a 3.5% bandwidth two-pole Chebyshev filter with transmission zeros at 37 GHz, 2.7% and 4.3% bandwidth four-and five-pole chebbershev filters at 60 GHz, and an 8% bandwidth elliptic filter at 60GHz.
Abstract: High-performance planar micromachined filters at 37 and 60 GHz are presented. The filters consist of a 3.5% bandwidth two-pole Chebyshev filter with transmission zeros at 37 GHz, 2.7% and 4.3% bandwidth four- and five-pole Chebyshev filters at 60 GHz, and an 8% bandwidth elliptic filter at 60 GHz. Silicon micromachining techniques combined with micropackaging have been applied to allow for very high-Q resonators resulting in low-loss filters. The 37-GHz two-pole filter exhibits a 2.3-dB port-to-port insertion loss. The 2.7% and 4.3% four- and five-pole Chebyshev filters at 60 GHz exhibit 2.8- and 3.4-dB insertion loss, and the 8% elliptic filter exhibits a 1.5-dB insertion loss. These values show a large reduction of insertion loss compared to conventional planar techniques, and can be used for planar low-cost millimeter-wave wireless communication systems.
182 citations
TL;DR: In this paper, a folded substrate integrated waveguide (FSIW) cavity is analyzed theoretically, and the results show the advantage of wide out-of-band rejection and compact size.
Abstract: In this paper, a folded substrate integrated waveguide (FSIW) cavity is analyzed theoretically. Formulae for the determination of the dimensions of the FSIW cavity have been deduced. To verify the proposed formulae, simulated results are compared with the results of the formulae and good agreement has been observed between them. An example filter working at 8 GHz is designed and fabricated. Good agreement between the simulated and the measured results has been obtained. Result shows the advantage of wide out-of-band rejection and compact size.
75 citations
07 Jun 1998
TL;DR: In this paper, the authors describe the design and the realization of two membrane supported microstrip millimeter-wave planar bandpass filters, which exhibit transmission zero and a 2.3 dB port-to-port insertion loss for the 37 GHz 3.5% bandwidth 2-pole filter.
Abstract: This paper describes the design and the realization of two membrane supported microstrip millimeter-wave planar bandpass filters. Both filters exhibit transmission zeros and a 2.3 dB port-to-port insertion loss for the 37 GHz 3.5% bandwidth 2-pole filter and a 1.5 dB insertion loss for a 60 GHz 8% bandwidth 4-pole filter. The use of membrane technology allows a significant reduction of insertion loss, combined with a reproducible, low cost fabrication process.
51 citations
TL;DR: In this paper, the edge-suspended structures were realized by a TMAH solution consisting of 5 wt% TMAHA, 1.6wt% Si and 0.5wt % NH42S2O8.
Abstract: This paper reports the micromachining techniques for fabricating edge-suspended RF/microwave passive components, which are proposed to deliver enhanced performance without sacrificing their mechanical strength and reliability. The fabrication incorporates ICP-DRIE dry etching and TMAH anisotropic etching techniques, which are both CMOS compatible. The edge-suspended structures were realized by a TMAH solution consisting of 5 wt% TMAH, 1.6 wt% Si and 0.5 wt% (NH4)2S2O8. This solution offers effective etching of silicon along the {100} and {110} planes, while having negligible etching on aluminum and {111} planes. The layout requirement for achieving edge-suspended passive components is also outlined on the basis of the analysis of the anisotropic etching along different crystal orientations. Using the techniques described here, high performance spiral inductors and coplanar waveguides (CPW) with significantly reduced loss are demonstrated. For a three-turn 4.5 nH inductor, a 70% increase (from 6.8 to 11.7) in maximum Q-factor and a 57% increase (from 9.1 GHz to 14.3 GHz) in self-resonance frequency are obtained with an 11 µm suspended edge in 25 µm wide lines compared to the conventional inductors without being micromachined. A 50 Ω edge-suspended CPW exhibits a reduction in insertion loss, from 2.4 dB mm−1 in a conventional CPW to 0.4 dB mm−1 at 39 GHz.
15 citations
"Silicon micromachined K-band filter..." refers background in this paper
...Also, TMAH etching has the advantages of low process cost, simple equipment, better surface smoothness and lower environmental pollution [6] ....
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