The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc.

Experimental Studies on Cooled Millimeter Wave Mixers

Antti V. Räisänen

Thesis for the degree of Doctor of Technology to be presented with due permission for public examination and criticism in Auditorium S4 at Helsinki University of Technology (Espoo, Finland) on the 19th of December, 1980, at 12 o'clock noon.

Dissertation in PDF format (ISBN 951-22-8372-7)   [1610 KB]
Dissertation is also available in print (ISBN 951-666-127-0)


The design and performance of two cooled mm-wave mixers is described. A Josephson point contact mixer was designed for 30-40 GHz. The Nb point contact is located in a symmetrical Nb waveguide flange using suitable insulating material. This construction allows the junction to be adjusted at Troom and makes it mechanically stable against shocks and temperature cycling. At 36 GHz the conversion loss was measured to be 5 dB when using an IF of 60 MHz. The mixer works evenly at frequencies 30-40 GHz. A cooled Schottky diode mixer was designed for 75-120 GHz. New details of this mixer include improved waveguide, backshort, RF filter and IF matching and bias circuit designs. This mixer is used in a cooled receiver (15 K) where LO is coupled by an adjustable ring-filter. The mixer is followed by a 4.5-5.0 GHz IF system of TIF = 24 K. For this receiver DSB noise temperatures of TRDSB = 140-230 K have been measured at any LO frequency from 75 to 120 GHz. The best SSB receiver noise temperature measured is TRSSB = 275 K at 88 GHz including a quasi-optical feed system. This implies a mixer noise temperature of TMSSB < 100 K. Finally a discussion on noise temperature and noise figure calculations and noise measurements is presented.

Keywords: cooled millimeter-wave mixers, mm-wave mixers, design, performance, Josephson point contact mixer, 30-40 GHz, Schottky diode mixer, 75-120 GHz

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© 2006 Helsinki University of Technology

Last update 2011-05-26