Search

In this paper, the design of a novel planar narrowband microstrip filter is presented. The structure is designed and manufactured in microstrip technology, and it is formed by set of pairs of resonators of different lengths. The length of one resonator in each pair is adjusted so that a suitable odd resonance is tuned to the center frequency of the filter. The length of the other resonator is adjusted so that the next even resonance is tuned again to the center frequency of the filter. The different path of the signal in each resonator produces a cancellation of energy at a given frequency, therefore implementing a transmission zero in the insertion-loss response of the filter. First, this paper presents a design example of a single set of resonators (basic unit cell) working at the fifth and sixth resonances. Then, two basic unit cells working at the first and second resonances are first optimized, and then they are cascaded to show how higher-order filter responses can be implemented. The measured results confirm the theoretical predictions, and validate the new structures for high-selectivity applications. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 450–455, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20499 [ABSTRACT FROM AUTHOR]

An alternative configuration for an infinite coaxially end-fed waveguide phased-array antenna is explored. In the proposed configuration, the integration of the end-fed launcher and the output waveguide, rather than the waveguide in itself, acts as a basic radiator. This allows the design of more compact antenna elements. In order to analyze and optimize the structure, an accurate full-wave simulation tool based on the multimode admittance matrix representation is developed. Results are validated against state-of-the-art commercial CAD software. Numerical simulations involving singly and doubly tuned configurations are presented and discussed to illustrate the potential convenience of the proposed configuration and of the CAD tool developed. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 276–281, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10437 [ABSTRACT FROM AUTHOR]

This paper describes a number of broadside-coupled microstrip structures and their use for the implementation of high-selectivity multilayered filters. The broadside configuration allows for the introduction of cross couplings between nonadjacent resonators. The cross couplings can then be used to implement transmission zeros that can significantly increase the selectivity of the filters. Furthermore, the investigation shows that the amount of coupling can be considerably increased if the resonators are broadside coupled, thus easily allowing the implementation of broadband filters. Measured results are shown to agree with predictions, thereby fully validating the new structures described. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 295–302, 2001. [ABSTRACT FROM AUTHOR]

Low-loss performance is one of the main drivers in the design of microwave filters and diplexers. In this paper, we propose a simple, low-cost solution to this problem. Measured responses of specific designs are also included, indicating that the solution proposed is indeed practical and cost effective. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 27: 7–9, 2000. [ABSTRACT FROM AUTHOR]