Theoretical Determination of Equivalent Circuit Parameters for Double Electrode SAW Interdigital Transducers

2013

Elect Comm in Japan

Leaky surface acoustic wave (LSAW) devices on Al-electrode/36-48° YX-LiTaO 3 substrates have seen wide use as filters and duplexers in cell phones because they possess a suitable electromechanical coupling factor and reflection coefficient, and a good Q factor for cell phones. In this paper, a new LSAW structure consisting of upper Al electrodes stacked on lower grooved Cu electrodes in Li-TaO 3 is proposed and compared with Al electrodes (0.1 λ)/42° YX-LiTaO 3 , which have been considered the best structure. We have been able to improve the characteristics of the LSAW.

Section: Theoretical Calculationsmentioning

confidence: 99%

Section: Theoretical Calculationsmentioning

confidence: 99%

Improvement of characteristics of leaky surface acoustic wave on LiTaO₃

2013

Elect Comm in Japan

“…Figure 1 shows the configurations of various electrodes formed on a substrate and in a substrate of 10° rotated YX-LiNbO 3 , based on an analysis [13,14] using the finite element method (FEM). We fabricated a SAW resonator using a Cu electrode and confirmed that the configuration with an embedded electrode yielded greater bandwidth.…”

Section: Introductionmentioning

confidence: 99%

“…We fabricated a SAW resonator using a Cu electrode and confirmed that the configuration with an embedded electrode yielded greater bandwidth. Figures 2 to 5 show the electromechanical coupling factor for the electrodes and the reflection coefficient [13][14][15] at one finger in the shorted electrode. In the BPF type, a 6.8% variable range was obtained in a tunable filter formed with a fixed capacity on a substrate instead of a variable capacity.…”

Section: Introductionmentioning

confidence: 99%

Ultra‐wideband SAW resonator composed of grooved Cu electrodes and its application to tunable filters

2013

Elect Comm in Japan

A cognitive radio system, which is being investigated in order to use limited frequency resources effectively, requires a tunable filter with a wide variable frequency range. A wideband resonator is required to realize a tunable filter. It was reported that a resonator composed of a Cu electrode/15° YX-LiNbO 3 had a large bandwidth of 12%. We attempted to fabricate a one-port resonator composed of a grooved Cu electrode/4° YX-LiNbO 3 . This resonator was applied to a tunable filter, and a tunable filter having a tunable range of 6.8% in the center frequency was experimentally realized using a bandpass-type filter circuit, and one having a tunable range of 9 to 12% was theoretically realized using a ladder-type filter circuit.

“…1 shows a dependence of electro-mechanical coupling factor on (a) a conventional structure of a Cu electrode on 4°Y-X·LiNbO 3 and (b) a structure of a grooved Cu-electrode /4°Y-X·LiNbO 3 as a function of the Cu thickness. The coupling factor was calculated by using FEM [6] [7]. Broken and solid lines show LSAW and Love wave without the leaky component, respectively, in Fig.1.…”

Section: Introductionmentioning

confidence: 99%

Band pass type of tunable filters composed of ultra wide band SAW resonators by adjusting capacitors connected SAW resonators

2011 IEEE International Ultrasonics Symposium

2011

Authors realized a one port surface acoustic wave (SAW) resonator composed of grooved-Cu-electrodes/4°Y-X· LiNbO 3 with an ultra wide bandwidth of 17 %. This time, the authors fabricated band pass type tunable filters using the SAW resonators instead of inductances and 2 kind of capacitors of interdigital capacitors (IDCs) and Si-diode variable capacitors. As a the result, when the IDCs were used, the tunable filter with the frequency tunable range of 6.8 % has been obtained by using 3 kinds of LiNbO 3 substrates having different capacitances of IDCs and the same designed SAW resonators. On the other hand, when the Si-diode variable capacitors were used, by applying the voltage of 1.2 V to 10 V to the Si variable capacitors (Toshiba JDV2S71E) in order to adjust the capacitance, a tunable filter with the frequency tunable range of 6.1% has been continuously obtained for the first time.