IEEE MTT-S 2008 International Microwave Symposium Technical Program

Session: TH3A	Microacoustic Frontend Technologies
Chair:	Clemens Ruppel, EPCOS AG
Co-Chair:	Robert Weigel, University of Erlangen-Nuremberg
Abstract:	In this session novel developments and future trends in the design of microwave acoustic components are addressed. The session starts with novel WCDMA duplexers, proceeds with ultraminiature ISM filters, FBAR oscillators,and highly stable SAW filters, and concludes with a new measurement technique for both SAW and BAW devices.

TH3A-01	BAW/SAW/IPD hybrid type duplexer with Rx balanced output for WCDMA Band I
1335	T. Nishihara¹, M. Iwaki¹, G. Endo², X. Mi¹, S. Taniguchi¹, M. Ueda¹, Y. Satoh¹, ¹Fujitsu Laboratories Ltd., Akashi, Japan, ²Fujitsu Media Devices Limited, Yokohama, Japan
	This paper describes a 3.0 x 2.5 x 0.7 mm3 wideband code division multiple access (WCDMA) Band I duplexer with receiver (Rx) balanced output we developed. The low-loss and power-durable film bulk acoustic resonator (FBAR) and the single-to-balanced double mode SAW (DMS) were utilized for the transmitter (Tx) and the Rx filter respectively. It was experimentally confirmed that the 2nd distortion of FBAR was significantly worse than that of the surface acoustic wave (SAW). In order to suppress the 2nd harmonic due to the nonlinear distortion of the duplexer and the power amplifier (PA), a notch circuit was implemented at the antenna port using our high-Q Integrated Passive Devices (IPD) technology. As a result, we realized the duplexer with the suppressed nonlinear distortion as well as the excellent filter response.

TH3A-02	Selection of Micro-Acoustic Technologies for the Realization of Single-ended / Balanced WCDMA Duplexers
1325	T. Metzger, M. Maier, H. Klamm, Z. Kovats, D. Ritter, G. Maurer, P. Selmeier, Epcos AG, Munich, Germany
	With the increasing number of frequency bands for WCDMA applications, also the need for miniaturized duplexer solutions increases in order to realize multi-band, multi-mode mobile phones. With SAW and BAW, two well established micro-acoustic technologies are available. For the realization of competitive CDMA duplexers like for the US-PCS band, so far the focus has been mainly on the provision of resonators with high quality factors and reduced temperature coefficient of frequency to realize filters with highest guaranteed steepness of filter skirts. With the large variety of duplexer requirements in the new WCDMA bands and the trend towards single-ended / balanced operation in the RX path, the constraints for technology selection have somewhat changed. Only when considering all critical parameters like center frequency, TX-RX bandgap, filter bandwidth, and insertion attenuation requirements, individual technology solutions for the different WCDMA frequency bands can be identified.

TH3A-03	An Ultra-Miniature, Low Cost Single Ended to Differential Filter for ISM Band Applications
1607	S. R. Gilbert, R. Parker, M. K. Small, U. B. Koelle, J. D. Larson III, R. C. Ruby, Avago Technologies, San Jose, United States
	We present a filter for the 2.4 GHz ISM band that has both filtering and balun functionality to deliver a single ended to differential (SE2DE) filter response and 4:1 impedance transformation. We integrate the balun and filter response into a single chip using two FBAR resonators stacked one on top of the other and separated by a thin, low acoustic impedance material. True SE2DE behavior is achieved by dividing the bottom FBAR into two 100 Ohm resonators and hooking them in parallel to present a 50 Ohm impedance to the endpoint. The two 100 Ohm resonators forming the top of the stack are connected in series to present a differential output impedance of 200 Ohms. Since the entire device is not much larger than a single 50 Ohm resonator, the total die size is extremely small (much smaller than a typical FBAR half ladder filter utilizing 4 to 8 resonators).

TH3A-04	A 2 GHz oscillator using a monolithically integrated AlN TFBAR
1117	M. Norling¹, J. Enlund², I. Katardjiev², S. Gevorgian¹, ¹Chalmers University of Technology, Göteborg, Sweden, ²Uppsala University, Uppsala, Sweden, ³Ericsson AB, Mölndal, Sweden
	A 2 GHz oscillator based on a solidly mounted AlN Thin-Film Bulk Acoustic Resonator (TFBAR) is reported. The oscillator is realised as a silicon-on-silicon Multi-Chip Module (MCM) where all passive elements, including the TFBAR, are monolithically integrated on a High-Resistivity Silicon (HRS) carrier. SiGe transistors are flipchip mounted on the MCM carrier.

TH3A-05	Miniature Surface Acoustic Wave Devices with Excellent Temperature Stability using High Density Metal Electrodes and SiO2 film
1064	M. Kadota, T. Nakao, K. Nishiyama, S. Kido, Murata Mfg. Co., Ltd., Yasu-shi, Japan
	Currently, miniature surface acoustic wave (SAW) devices (filters and duplexers) with a good temperature stability are strongly required. In order to realize its requirement, various SAW substrates combining a high density metal electrode, a SiO2 film, and LiTaO3 or LiNbO3 substrate were researched. Their combinations offer excellent properties such as large electrode reflection coefficient, large mechanical coupling factor, low velocity, and good temperature stability. This paper reviews realization of miniature SAW devices with low insertion loss and good temperature stability, such as SAW duplexers for personal communication service system in the United States (US-PCS) and wide band code division multiple access system (W-CDMA) using thier combinatios.

TH3A-06	A Fast Scanning Laser Probe Based on Sagnac Interferometer for RF Surface and Bulk Acoustic Wave Devices
1065	K. Hashimoto¹, K. Kashiwa¹, T. Omori¹, M. Yamaguchi¹, O. Takano², S. Meguro², K. Akahane², ¹Chiba University, Chiba, Japan, ²Neoark, Hachi-Ohji, Japan
	This paper describes development of a new laser probe for radio frequency (RF) surface and bulk acoustic wave (SAW/BAW) devices. The Sagnac interferometer was employed for the selective detection of RF vertical motion caused by the RF SAW/BAW propagation. A high pass characteristic of this interferometer makes the measurement very insensitive to the low-frequency vibration. Combination of this feature with the advanced scanning technique and optimized detection system enables us to maximize the scanning speed without sacrificing the signal-to-noise ratio and sensitivity of the measurement. The system was applied for the characterization of RF SAW/BAW devices, and its effectiveness was demonstrated.

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