cated bandpass filter is at 2.47 GHz and the fractional bandwidth is 5%. The measured insertion loss and return loss of the filter is Ϫ3.68 and Ϫ14.92 dB, respectively. The measured center frequency, insertion loss and return loss of the fabricated filter are in agreement with simulated results. ACKNOWLEDGMENT The authors are grateful to the National Science Council of R.O.C. for financial support under the project No. NSC 94-2215-E-214-007. REFERENCES 1. M.L. Hsieh, L.S. Chen, S.M. Wang, C.H. Sun, M.H. Weng, M.P. Houng, and S.L. Fu, Low-temperature sintering of microwave dielectrics (Zn,Mg)TiO 3 , Jpn J Appl Phys 44 (2005), 5045-5048. 2. R. Levy, R.V. Snyder, and G. Matthaei, Design of microwave filters, IEEE Trans Microwave Theory Tech 50 (2002), 783-793. 3. J.S. Hong and M.J. Lancaster, Couplings of microstrip square open-loop resonators for cross-coupled planar microwave filters, IEEE Trans Microwave Theory Tech 44 (1996), 2099-2109. 4. J.T. Kuo, M.J. Maa, and P.H. Lu, A microstrip elliptic function filter with copact miniaturized hairpin resonators, IEEE Microwave Guided Wave Lett 10 (2000), 94-95. 5. C.S. Ahn, J. Lee, and Y.S. Kim, Design flexibility of an open-loop resonator filter using similarity transformation of coupling matrix, IEEE Microwave Wireless Compon Lett 15 (2005), 262-264. 6. J.S. Hong and M.J. Lancaster, Design of highly selective microstrip bandpass filters with a single pair of attenuation poles at finite frequencies, IEEE Trans Microwave Theory ABSTRACT: Rapid prototyping by an extrusion freeforming technique, of ceramic metamaterials based on a woodpile structure at millimeterwave frequencies has been performed. The finite difference time domain technique is applied for the design and characterization of the proposed metamaterials. The transmittance of the millimeterwave metamaterials is measured in the range of 75-110 GHz. Both measurement and simulation results are in good agreement.

This book describes the application of high-temperature superconducting materials to microwave devices and systems. It deals with the fundamentals of the interaction between microwaves and superconductors, and includes a basic description of how microwave devices can be constructed using these materials. Since the discovery of high-temperature superconductors in 1986 there has been an enormous effort worldwide to develop and characterize these materials. Work on applications has proceeded more slowly however. Nevertheless, commercial applications are now beginning to be possible, including use in passive microwave devices. The advantages of using high-temperature superconductors in these devices is carefully described by the author, enabling scientists and engineers to form a complete understanding of the subject. The rest of the book is devoted to examples of superconducting microwave filters, antennas and systems. The examples chosen relate not only to what can be achieved at present, but indicate the trends for future research and what may be expected for superconducting devices in the future.

When an electric field is applied to a ferroelectric material, the microwave permittivity undergoes a substantial change. This change in permittivity can be utilized in microwave devices to produce frequency-agile functions. This paper is a comprehensive review of the work on ferroelectric materials; this includes models of the ferroelectric permittivity and loss tangent, as well as methods of measurement of these properties. New measurements are presented on thin-film strontium titanate and single-crystal strontium barium titanate substrates. These results are compared with the model. A brief discussion is given of the applications of ferroelectric material in microwave devices.

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A novel type of dual-mode microstrip bandpass filter using degenerate modes of a meander loop resonator has been developed for miniaturization of high selectivity narrowband microwave bandpass filters. A filter of this type having a 2.5% bandwidth at 1.58 GHz was designed and fabricated. The measured filter performance is presented.