Low‐loss silicon‐on‐quartz (SoQ)‐based aperture‐coupled antenna on RF MEMS packaging platform

Abstract

This letter presents a micromachined aperture‐coupled antenna which improves antenna performances as well as simplifies a fabrication process. The SoQ (silicon‐on‐quartz) bonding and BCB (benzocyclobutene) adhesive bonding are employed for a radio frequency microelectro‐mechanical system (RF‐MEMS) packaging platform. The SoQ/BCB packaging platform makes the air cavity and the quartz substrate where the aperture‐coupled antenna is stacked. Therefore, radiation performances can be enhanced from low‐loss air/quartz substrates while a silicon substrate has almost no effects on radiation. Furthermore, the proposed method enables simultaneous integration of the antenna with the RF MEMS devices through a single packaging process. In this letter, the antenna is manufactured based on the proposed method and the fabrication process is carefully described. The s‐parameters and shear strength are measured to evaluate both of antenna and packaging performances. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 125–128, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24874

Package-Platformed Linear/Circular Polarization Reconfigurable Antenna Using an Integrated Silicon RF MEMS Switch

“…The top substrate is vertically stacked onto the bottom glass substrate and bonded with it using the BCB rim as an intermediate adhesive layer. BCB, a well-known RF packaging material, is used as a bonding material because of its excellent microwave properties and good resistance to gas and moisture [10]. Silicon rim is also used with BCB to obtain enough space for the RF MEMS switch to be packaged as well as to adjust the distance between the bottom and top substrates for optimal electromagnetic coupling.…”

“…Fabrication of the top substrate is based on the SoQ/BCB platform developed in our group [10]. After bonding 500-μm-thick fused quartz and silicon wafers, they are thinned down to 300 μm for quartz and 85 μm for silicon, respectively, and a 500-nm-thick gold radiation patch is patterned on the quartz (Fig.…”

“…On the other hand, a radiating patch is formed on one side of the top fused quartz substrate with patterned rectangular silicon/BCB rims on the other side. The top substrate, in combination with air below it, plays a role of a dielectric material for the radiating patch, and thus fused quartz is chosen as a substrate material thanks to its low-loss properties at BCB, a well-known RF packaging material, is used as a bonding material because of its excellent microwave properties and good resistance to gas and moisture [10]. Silicon rim is also used with BCB to obtain enough space for the RF MEMS switch to be packaged as well as to adjust the distance between the bottom and top substrates for optimal electromagnetic coupling.…”

“…The proposed antenna can simply switch its polarization state from LP to CP by connecting a stub to a ring slot coupled to a radiation patch with electrostatic actuation of the RF MEMS contact switch. The MEMS switch is efficiently integrated with the antenna into the form of a vertically-stacked compact package using the silicon-on-quartz (SoQ)/bisbenzocyclobutene (BCB) platform previously developed by our group [10]. Details of the antenna design, fabrication process, and the measured antenna performances will be described.…”