Chris Feng

Ultra-miniature coupled resonator filter with single-layer acoustic coupler

Coupled resonator filters designed using a single-layer coupler require coupling materials with an acoustic impedance less than 5.0 MRayl. Carbon-doped oxide, with an acoustic impedance of 4.8 MRayl and an acoustic attenuation of 200 to 600 dB/cm at 1 GHz, can be used as a single-layer coupler to produce a competitive 2-stage coupled resonator filter for cellular handset applications in the gigahertz frequency range. The electrical response of our filter is superior to that of coupled resonator filters using a traditional acoustic mirror as the coupling element. We present an ultra-miniature 0.58 mm times 0.38 mm coupled resonator filter operating at a frequency of 2.15 GHz.

11E-3 A Thermally Stable CMOS Oscillator Using Temperature Compensated FBAR

This paper presents a passively temperature compensated CMOS oscillator utilizing Film Bulk Acoustic Resonator (FBAR). The resonator exhibiting f-Q product of 2~3times1012 sec-1 is comprised of molybdenum (Mo), aluminum nitride (AlN), and a compensation material that has positive temperature coefficient of Youngs modulus. The 600 MHz oscillator consumes 6.6 mW from a 3.3 V supply and achieves an excellent phase noise performance of -102 dBc/Hz, -132 dBc/Hz, and -151 dBc/Hz at 1 kHz, 10 kHz, and 100 kHz carrier offset, respectively. The oscillators temperature-dependent frequency drift is less than 80 parts per million (ppm) over a temperature range of -35 to +85degC.

Performance degradation effects in FBAR filters and resonators due to lamb wave modes

We describe the effect of Rayleigh-Lamb Modes on the electrical performance of a Film Bulk Acoustic Resonator (EBAR). The mode structure, shape, and Q have a large effect on FBAR response. Keywords-FBAR, Piston Mode, Lamb Mode, ω-k, Q, Rs, Rp

FBAR resonator figure of merit improvements

Free-standing Bulk Acoustic Resonator (FBAR), as one type of bulk acoustic wave (BAW) devices, has extremely high Q to enable excellent filter performance, and has been successfully applied to the wireless communication market. The Bode equation to calculate the unloaded Q is used to map the Avago FBAR product line resonator Rp values. The manufacturing Rp values from old and new generations of FBAR products are collected and compared to demonstrate the importance of the figure of merit (FOM) improvements.