Onoh, Greg Nwachuku (1982) Meanderline networks incorporating P.I.N. diodes for digital multiplexing applications. PhD thesis, University of Warwick.

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Abstract

The design of a two-state multiplexer is presented in this project. The design is based on the switching actions of a p.i.n. diode and the filtering characteristics of a meander line. The diodes used are MEDL types DC 2518G and DC 2418A. The diodes were characterized and the elements of the equivalent circuit found using an insertion loss technique. Effective biasing and driving of the diodes were achieved using a three element low-pass filter and a two-stage transistor driver respectively.
The design of the meander line networks was based cm a new technique developed by the author. The technique involves the evaluation of the coupling and susceptance loading parameters of the meander lines. These parameters were evaluated frcm the quasi-static consideration using a function sub-program, fifteen meanderline circuits were designed. The response of the circuits showed an isolation of 12.2dB in the stop-band an insertion loss of only 0.8dB in the passband far an 11-turns meander lines. Comparison of the measured and computed results shewed a disparity less than 5%.
Five categories of digital filters were designed. The basic circuit is a meander line having p.i.n. diode terminated stubs inside the meander-loops. Hie diodes serve as ideal transmission-reflection devices, providing either short or open circuit terminations to the stubs depending on the bias applied to them. When a TTL 'O' is driving the diodes a bandpass filter results, but when the drive is a TIL '1', the bandpass filter is converted to a bandstop filter. The maximum transmission coefficient in the 'O' state was |S211 " 0.95 and in the '1' state the minlmtm transmission coefficient was |S211 “ 0.0135. The maximum bandwidth measured was 39.5%.
These filters were cascaded to form a two and three channel multiplexers. Fbr the diplexer, an assynmetric Y-Junction was used in the design. The measured isolation between the two channels was 25.4dB. For the triplexer, a matched cross-junction was used as the camion junction. The isolation between channels 1 and 2 was 21dB, while between 2 and 3 it was 10.45 dB.

Item Type:	Thesis (PhD)
Subjects:	T Technology > TK Electrical engineering. Electronics Nuclear engineering
Library of Congress Subject Headings (LCSH):	Electric power transmission, Diodes, PIN diodes, Microwave circuits, Electric filters, Electric networks
Official Date:	June 1982
Dates:	Date Event June 1982 Submitted
Institution:	University of Warwick
Theses Department:	Department of Engineering
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Shurmer, Harold Victor
Sponsors:	Nigeria, British Council
Extent:	xi, 191, [5] leaves : illustrations
Language:	eng

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