© 2013 El Hassan et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Techniques for Tuning BAW-SMR Resonators for the 4 Generation of Mobile Communications

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.

This paper presents the feasibility of a new method to tune the Bulk Acoustic Wave - Solidly Mounted Resonator (BAW-SMR) filters by adding capacitors to the shunt resonators and by controlling these capacitors using CMOS transistors that act as switches. The tunable BAWSMR filter is realized in a ladder topology. It is 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 @ ± 30 MHz of the bandwidth. Moreover, a measured shift of 0.5% of the centre frequency (2.44 GHz) towards higher frequencies is obtained. This tunable BAW-SMR filter has reduced dimensions (1035*1075 µm 2 ).

This article presents a study of ladder-lattice bulk acoustic wave (BAW) filters. First, a review of BAW technology and filters topologies is addressed. Next, a mixed ladder-lattice BAW filter for application on W-CDMA reception front-ends (2.11–2.17 GHz) is presented. An improved solidly mounted resonators (SMR) technology was used for the filter implementation. The filter synthesis methodology is briefly described. Layout guidelines are discussed enabling an optimized filter design. The filter on-wafer measurement results are as follows: -3.55 dB of insertion loss, -8.7 dB of return loss, an isolation higher than -47 dB at the transmission band (1.92–1.98 GHz) and an improved selectivity (-30 dB at 2.14 GHz ± 60 MHz). Therefore, we can observe that the mixed topology combines the advantages of ladder and lattice networks, having very steep responses and an improved isolation at undesired bands. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008.

This paper presents a BAW-SMR filter using a combined ladder-lattice topology for application in W-CDMA reception front-ends (2.11 - 2.17 GHz). The combined topology allies the advantages of both network types, having very steep responses and high isolation at undesired bands. The design of filter was simulated using a combined 2D EM-acoustical analysis procedure, it presents: 1.6 dB of insertion loss, -10 dB of return loss and isolation higher than -48 dB at TX band (1.92 - 1.98 GHz).