4.5 GHz Lithium Niobate MEMS Filters with 10% Fractional Bandwidth for 5G Front-ends

Abstract

This paper presents a new class of micro-electro-mechanical system (MEMS) C-band filters for 5G front-ends. The filter is comprised of resonators based on the first-order asymmetric Lamb wave (A1) mode in thin film lithium niobate. Two filters have been demonstrated at 4.5 GHz with sharp roll-off, flat in-band group delay, and spurious-free response over a wide frequency range. The first design shows a fractional bandwidth (FBW) of 10%, an insertion loss (IL) of 1.7 dB, an out-of-band (OoB) rejection of -13 dB, and a compact footprint of 0.36 mm2, while the second design shows an FBW of 8.5%, an IL of 2.7 dB, an OoB rejection of -25 dB, and a footprint of 0.9 mm^2. The demonstrations herein mark the largest fractional bandwidth (FBW) achieved for acoustic-only filters at 5G frequencies.

3 pages, 7 figures

References in corpus (1)

• Toward Ka Band Acoustics: Lithium Niobate Asymmetrical Mode Piezoelectric MEMS Resonators

Cited by in corpus (7)

• Thin-Film Lithium Niobate Acoustic Filter at 23.5 GHz with 2.38 dB IL and 18.2% FBW
• 5-GHz Antisymmetric Mode Acoustic Delay Lines in Lithium Niobate Thin Film
• 23.8-GHz Acoustic Filter in Periodically Poled Piezoelectric Film Lithium Niobate With 1.52-dB IL and 19.4% FBW
• C-Band Lithium Niobate on Silicon Carbide SAW Resonator With Figure-of-Merit of 124 at 6.5 GHz
• Transferred Thin Film Lithium Niobate as Millimeter Wave Acoustic Filter Platforms
• Visualization of Acoustic Power Flow in Suspended Thin-film Lithium Niobate Phononic Devices
• K-band LiNbO3 A3 Lamb-wave Resonators with Sub-wavelength Through-holes