access icon free 5 GHz Band n79 wideband microacoustic filter using thin lithium niobate membrane

Microacoustic resonators made on suspended continuous membranes of LiNbO3 were recently shown to have very strong coupling and low losses at ≥5 GHz, suitable for high-performance filter design. Employing these simple resonator structures, the authors have designed, fabricated, and measured a 4.7 GHz bandpass ladder-type filter having 1 dB mid-band loss and 600 MHz bandwidth to address the 5G Band n79 requirements. The filter is fabricated on a monolithic substrate using standard i-line optical lithography and standard semiconductor processing methods for membrane release, starting with commercially available ion-sliced wafers having 400 nm thickness crystalline LiNbO3 layers. The filter is well-matched to a 50 Ω network and does not require external matching elements. Through accurate resonator engineering using our finite element method software filter design environment, the passband is spurious-free, and the filter provides better-than 30 dB rejection to the adjacent WiFi frequencies. This filter demonstrates the performance and scalable technology required for high-volume manufacturing of microacoustic filters >3.5 GHz.

Inspec keywords: acoustic resonator filters; lithium compounds; microwave filters; finite element analysis; band-pass filters; microwave resonators

Other keywords: microacoustic resonators; wideband microacoustic filter; finite element method software filter design; frequency 4.7 GHz; bandwidth 600.0 MHz; semiconductor processing methods; resonator engineering; resonator structures; LiNbO3; i-line optical lithography; ladder-type filter; lithium niobate membrane

Subjects: Filters and other networks; Finite element analysis; Acoustic wave devices; Waveguide and microwave transmission line components

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http://iet.metastore.ingenta.com/content/journals/10.1049/el.2019.1658
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Correspondence
This article has following corresponding article(s):
microacoustics