A hybrid-coupled tunnel-diode amplifier

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A hybrid-coupled tunnel-diode amplifier Holland, John Henry

Abstract

The analysis and design of a hybrid-coupled tunnel-diode amplifier is described, considering both the hybrid junction and the tunnel-diode circuitry. The fundamental theory of the tunnel diode is reviewed. The hybrid junction is in the form of a strip-line directional coupler which makes use of the inherent contra-directional coupling between two adjacent transmission lines. A complete analysis of the frequency dependence of the response of such a coupler is given. The amplifier is realized using the coupler and a pair of matched diodes terminating mutually isolated ports. To optimize the performance of this type of amplifier the design of the coupler is integrated with the design of the diode circuit. In doing so, account is taken of the frequency dependence of the hybrid junction, an aspect of the problem which has not been treated in the literature. As an example, an amplifier covering the VHF television channels is designed, and experimental results of a working model for a 50-ohm system are presented. The amplifier uses the periodicity of the directional coupler to provide two pass bands spanning Channels 2 to 6 (54 to 88 Mc) and Channels 7 to 12 (174 to 216 Mc), respectively. The two GE lN2939A tunnel diodes used for the amplifier provide a gain of 7.8 db ± 0.3 db for the lower band and 8.9 db ± 0.45 db for the upper band. The maximum input VSWR for the lower and upper bands are less than 2.3 and 3.2, respectively. The theoretical noise figure for a bias current of 0.7 ma is 3.79 db. It is found that the experimental results are in general agreement with the theory. Suggestions for improvement are given in cases where discrepancies do occur.

Item Metadata

Title	A hybrid-coupled tunnel-diode amplifier
Creator	Holland, John Henry
Publisher	University of British Columbia
Date Issued	1962
Description	The analysis and design of a hybrid-coupled tunnel-diode amplifier is described, considering both the hybrid junction and the tunnel-diode circuitry. The fundamental theory of the tunnel diode is reviewed. The hybrid junction is in the form of a strip-line directional coupler which makes use of the inherent contra-directional coupling between two adjacent transmission lines. A complete analysis of the frequency dependence of the response of such a coupler is given. The amplifier is realized using the coupler and a pair of matched diodes terminating mutually isolated ports. To optimize the performance of this type of amplifier the design of the coupler is integrated with the design of the diode circuit. In doing so, account is taken of the frequency dependence of the hybrid junction, an aspect of the problem which has not been treated in the literature. As an example, an amplifier covering the VHF television channels is designed, and experimental results of a working model for a 50-ohm system are presented. The amplifier uses the periodicity of the directional coupler to provide two pass bands spanning Channels 2 to 6 (54 to 88 Mc) and Channels 7 to 12 (174 to 216 Mc), respectively. The two GE lN2939A tunnel diodes used for the amplifier provide a gain of 7.8 db ± 0.3 db for the lower band and 8.9 db ± 0.45 db for the upper band. The maximum input VSWR for the lower and upper bands are less than 2.3 and 3.2, respectively. The theoretical noise figure for a bias current of 0.7 ma is 3.79 db. It is found that the experimental results are in general agreement with the theory. Suggestions for improvement are given in cases where discrepancies do occur.
Genre	Thesis/Dissertation
Type	Text
Language	eng
Date Available	2011-11-15
Provider	Vancouver : University of British Columbia Library
Rights	For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
DOI	10.14288/1.0302295
URI	http://hdl.handle.net/2429/39004
Degree	Master of Applied Science - MASc
Program	Electrical and Computer Engineering
Affiliation	Applied Science, Faculty of; Electrical and Computer Engineering, Department of
Degree Grantor	University of British Columbia
Campus	UBCV
Scholarly Level	Graduate
Aggregated Source Repository	DSpace

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UBC_1963_A7 H6 H9.pdf -- 4.74MB

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Rights

For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.