Ali TOKER, Metin YAZGI

Bant geçiren filtre yapılı CSSDA' nın analizi, tasarımı ve performansı

Bu çalışmada, kaskatlanmış tek hücreli dağılmış parametreli kuvvetlendiricilerin (CSSDA) yapay hatlarının gerçekleştirilmesi için bant geçiren filtre yapısı önerilmekte ve bant geçiren filtre yapılı CSSDA 'ların temel analiz ve tasarımı verilmektedir. CSSDA 'mn alt frekans bölgesinin bir kısmı kutupluma elemanları sebebiyle kullanılamaz. Yapay hatların bant geçiren filtre (BP) yapılı tasarlanması durumunda kullanılamayan frekans bölgesi kazanç-frekans bandına katılabilir. Bundan dolayı BP yapılı CSSDA 'lardan LP yapılı CSSDA 'lara göre daha geniş bir bant elde edilebilir. CSSDA 'mn kazancı arahat sonlandırma empedanslarının $(Z_{0int})$ değerleri arttırılarak band genişliği azaltılmaksızın yükseltilebilir. Bu çalışmada maksimum $(Z_{0int})$, değerinin belirlenmesi için grafiksel bir yöntem tanıtılmaktadır. Simülasyon sonuçları BP yapılı CSSDA'ların avantajım ortaya koymaktadır.

Analysis, design and performance of CSSDA with bandpass filter structure

The conventional distributed amplifier (CDA) is one of the most investigated and realized broadband circuits. However the maximum gain obtainable from the CDA is limited to about 7-14 dB. To overcome this disadvantage, a novel broadband amplifier has been presented in the literature, which is called cascaded single-stage distributed amplifier (CSSDA). The gain of a CSSDA is significantly higher than that of the CDA designed for a given number of active devices. A CSSDA has three different artificial lines: the input line, the interstage line and the output line. In previous studies, all these lines have been analyzed and designed as lowpass (LP) structured lines. On the other hand, when bias components are taken into the account, it will become apparent that these lines are similar to bandpass structured lines. There is a bandpass structure in the literature, which has been proposed for shifting the gain-frequency band of the CDA. This structure includes all the necessary bias components. Hence, if one uses the bandpass structure for realizing the artificial lines, better gain-frequency performance can be obtained for the CSSDA. The gain of CSSDA can be increased, by increasing the interstage termination impedance $(Z_{0int})$ without decreasing the bandwidth. In this paper, the basic analysis and design of the proposed BP structured CSSDA has been introduced. Also, a graphical method for the determination of the maximum $(Z_{0int})$ is suggested. Simulations have been conducted on CSSDAs with the LP and BP structured artificial lines and the results indicating the advantages of the BP structure are presented.

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