The Fabrication of the Low Loss Transmission Line and Low Pass Filter using Surface Microelectromechanical Systems Technology

Abstract

In this study, we first fabricated a new GaAs-based dielectric-supported air-gap microstrip lines (DAMLs) by the surface microelectromechanical systems (MEMS) technology, and then fabricated the low-pass filter (LPF) for the Ka-band using those DAMLs. We elevated the signal lines from the surface in order to reduce the substrate dielectric loss and to obtain low losses at the millimeter-wave frequency band with a wide impedance range. We fabricated LPFs with DAMLs for Ka-bands, and we were able to reduce the insertion loss of LPFs by reducing the dielectric loss of the DAMLs. Miniaturization is essential for integrating LPFs with active devices, so we fabricated a LPF with the slot on the ground metal to reduce the size of the LPF. We compared the characteristics of the LPF with a slot and the LPF without the slot.

A millimeter‐wave slow‐wave bandpass filter using compact microstrip stepped‐impedance hairpin resonator with inter‐digital capacitor on GaAs substrate

“…In this paper, a new slow-wave band-pass filter (BPF) using a stepped-impedance resonator (SIR) hairpin with IDC is proposed using GaAs surface micromachining in the 56-GHz range. The microstrip line is elevated by the polyimide dielectric post using the surface-micromachining technique and then it has an airgapped area between the signal line and the ground metal [3]. Since the DAML structure is compatible with the conventional monolithic microwave integrated circuit (MMIC) technologies, it is possible to integrate the passive MEMS components on the active GaAs MMIC, which can make the cost lower and the size smaller with good performance.…”

A 60‐GHz GaAs micromachined slow‐wave bandpass filter using a microstrip stepped‐impedance hairpin resonator

“…Therefore, fabrication of the low-loss transmission line facilitates realization of the microstrip structure easily, without the complex processes such as via-hole and back metalization, because the signal line and the ground are on the same plane, even though it is a microstrip line. The DAML structure is compatible with conventional MMIC technologies; therefore, this structure can integrate passive MEMS components on active GaAs MMICs, which can lower the cost and size while maintaining good performance [4].…”

“…Planar monopole antennas are very attractive and suitable for application in UWB communication systems due to their wide impedance bandwidth, simple structure, and omnidirectional radiation pattern [1][2][3][4]. In order to improve the impedance bandwidth of planar monopole antennas, several techniques, such as using various disk shapes [1,2], a dual-fed antenna [3], and a bevel and shorting pin [4], have been studied.…”

“…In order to improve the impedance bandwidth of planar monopole antennas, several techniques, such as using various disk shapes [1,2], a dual-fed antenna [3], and a bevel and shorting pin [4], have been studied. However, UWB applications still require a compact antenna with the band-stop characteristic in order to avoid interference with existing 5.2/5.8-GHz WLAN systems, while maintaining ultra-wideband performance.…”

Millimeter-wave GaAs stepped-impedance hairpin resonator filters using surface micromachining

“…The DAML structure is compatible with the conventional MMIC technologies. Therefore, the DAML structure could integrate the passive MEMS components on the active GaAs MMIC, which can make the cost lower and the size smaller with good performance [2]. Microstrip stepped-impedance hairpin resonators have many attractive features [3] and can be used in satellite, mobile phones, and other wireless communication system.…”