Stacked crystal resonator: A highly linear BAW device

Abstract

Besides small size, exceptional insertion loss and outstanding isolation, bulk acoustic wave (BAW) filters and duplexers are often the preferred choice in the transmit path of mobile frontend due to their excellent power handling capabilities. However, they exhibit a nonlinear behavior, causing generation of higher harmonics and a sensitivity of the resonance frequency towards a DC voltage bias. In this paper we present a new BAW device, a stacked crystal resonator (SCR), which intrinsically cancels out the second order nonlinearity and compare it to standard BAW resonators and current solutions for improved linearity. Measurements of first devices demonstrate a 30dB improvement in worst case second order harmonic generation of a SCR over a standard BAW solid mounted resonator. Furthermore, the frequency sensitivity on a DC voltage bias is reduced by a factor of 20 and the coupling coefficient increased by 10%.Bulk acoustic wave resonator; BAW; nonlinearity; stacked crystal resonator; SCR

Analysis and verification on second-order nonlinearity in radio frequency bulk acoustic wave devices employing temperature compensation films

“…Suppression of nonlinear signal generation in RF SAW and BAR devices is one of the most important subjects on the RF front end in recent cellular handsets. [22][23][24][25][26][27][28][29][30][31][32][33][34] Especially, the issue of second-order nonlinear products of BAR is well known. 22) In a standard FBAR consisting of piezoelectric AlN and top and bottom electrodes, several detailed investigations [31][32][33][34] have shown that the piezoelectric AlN is the dominant material contributing to the second-order nonlinear response.…”

Perturbation analysis of second-order nonlinearity and its effectiveness for radiofrequency bulk acoustic wave devices

“…Suppression of nonlinear signal generation in RF SAW/ BAW devices is one of the most important subjects concerning RF front-end modules in recent cellular handsets. [22][23][24][25][26][27][28][29][30][31][32][33][34] In particular, issues with second-order nonlinear products of BAWs are well known. 22) Therefore, clarification of nonlinear signal generation mechanisms in SAW/BAW devices is urgently required.…”

Perturbation analysis of nonlinear responses caused by transverse modes in AlN FBAR based on 2D scalar wave model

“…Linearity is one of the biggest research topics for RF SAW/ BAW duplexers and/or multiplexers, [1][2][3][4][5][6][7][8][9][10][11][12] and accurate and fast simulation tools are highly demanded for further suppression of nonlinear signal generation in these devices.…”