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. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/39004 |
| Date | January 1962 |
| Creators | Holland, John Henry |
| Publisher | University of British Columbia |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| 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. |
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