This paper proposes simple and precise nonlinear simulation techniques for surface acoustic wave (SAW) duplexers, especially for the in-band 3rd order nonlinear distortion, the socalled 'triple beat'. The simulation model is based on the nonlinearity of SAW stress vs. strain (nonlinear elasticity of SAW), and needs just one nonlinear parameter, which represents the 3rd order nonlinear coefficient for the elastic constant. The simulation results of the triple beat for 1.9 GHz Personal Communications Service (PCS) SAW duplexers demonstrate fairly good agreement with the measurements with an accuracy of less than 1 dB.

This paper describes the development of a miniaturized antenna duplexer for the W-CDMA application. As the required insertion loss in the W-CDMA system is severe even for the film bulk acoustic resonator (FBAR) technology, we propose a modified FBAR structure, which we called an AlN "just-etched" FBAR, to reduce acoustic losses. The characteristics of the proposed FBAR are verified by both simulation and experimental data and it is confirmed that the lateral-leakage of acoustic waves is successfully decreased. As results, the Q-factor at the anti-resonance and the effective k 2 are improved from 700 to 900, and 7.4% to 7.5%. The W-CDMA duplexer is designed using the proposed FBAR and integrated lumped elements for the compact and low-loss phase shifters. The insertion losses of the fabricated 3 x 3 mm 2 duplexers are as small as 1.5 dB and 1.6 dB in the Tx and the Rx band with a high isolation.

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We report new high-resolution photoabsorption data on the Lyman bands of H, obtained with a sample at very low vapour density and rather low temperature. The measurements were carried out by synchrotron spectroscopy, using the continuum emitted by the 500 MeV accelerator of the Physikalisches Institut in Bonn. Spectra were recorded in the first order of a 6000 line/" holographic grating, at a dispersion of 0.6 A mm-'.More complete photoabsorption data than previously available for the bands from (0,O) to (9,O) are presented and rotational constants are determined. They agree well with the best values in the current literature.

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