Tunability of bulk acoustic wave solidly mounted resonators using passive elements: Concept, design and implementation

• Published in: International journal of RF and microwave computer-aided engineering Vol. 21; no. 5; pp. 496 - 504
• Main Authors: Hassan, M. El, Kerherve, E., Deval, Y., David, J.B., Belot, D., Shirakawa, A.A.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.09.2011; Wiley
• Subjects: Acoustics; BAW filters; Electronics; Engineering Sciences; INT; Microwaves; Noise levels; passive elements; Radio frequencies; Resonators; SMR devices; Wireless communication
• ISSN: 1096-4290; 1099-047X; 1099-047X
• DOI: 10.1002/mmce.20554

This paper presents the impedance behavior of the bulk acoustic wave solidly mounted resonators (BAW‐SMR). Also, it shows the effects of the addition of passive elements (L, C) to this type of resonators. In addition, this article presents a tunable BAW‐SMR filter realized in a ladder topology used for the 802.11b/g standard (2.40–2.48 GHz). Mainly, the filter fulfills the requirements for the WLAN 802.11 b/g standard, presenting a measured −3.3 dB of insertion loss, –12.7 dB of return loss and selectivity higher than 33 dB at ±30 MHz of the bandwidth. This tunable BAW‐SMR filter has reduced dimensions (1035 × 1075 μm2). Moreover, we show how to shift the center frequency of this tunable filter toward higher and lower frequencies by adding passive elements. Measured shifts of −1.3% of the center frequency (2.44 GHz) toward lower frequency and +0.6% of the center frequency toward higher frequencies are obtained. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.