Characterization and Application of Lumped Double Crosstie Slow-Wave Transmission Lines

Hideki KAMITSUNA  Hiroyo OGAWA  

IEICE TRANSACTIONS on Electronics   Vol.E76-C    No.6    pp.968-976
Publication Date: 1993/06/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Microwave and Millimeter-Wave Technology for Advanced Functions and Size-Reductions)
MMIC,  DCT-SL W,  low-loss,  delay line,  hybrid,  

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This paper describes the characteristics and application of lumped double crosstie slow-wave transmission lines (DCT-SLWs) which we previously proposed. Firstly, the relationship between the DCT-SLW's characteristics and their parameters, i. e. triplate stripline widths and inductor resistances, are numerically and experimentally investigated. Excellent slow-wave lines with both high slow-wave factors (1240) and a wide characteristic impedance range (35100Ω) are achieved in good agreement with calculated results. A 50-Ω DCT-SLW that reduces circuit area more than 80%, and has an insertion loss less than that of 22-µm-wide TFMS lines is achieved by adapting a low-loss inductor in the frequencies below 14.5 GHz. Secondly, the application of DCT-SLW to non-dispersive, dispersive delay lines and branch-line hybrids is discussed. Specifically, very small 4-GHz-band branch-line hybrids are fabricated in a chip area of 0.7 mm2. Fundamental microwave circuits utilizing slow-wave lines in MMICs are demonstrated for the first time.