V.I. Tishchenko – Ph.D.(Eng.), Leading Research Scienntist, 

JSC «Scientific-production center «Almaz-Phazotron» (Saratov)

E-mail: STU1954@mail.ru

A.B. Danilov – Head of Departament, 

JSC «RPE «Almaz» (Saratov)

E-mail: danilovab@almaz-rpe.ru

The possibility of extending the operating frequency range of waveguide counter-directional couplers with a weak coupling by the frequency sensitivity of coupling and the minimum is considered. When coupling parallel waveguides is a common wide and a narrow wall, two variants of the implementation of counter-directional couplers are known. The first option is the Schwinger coupler with a pair of longitudinal slots. The second option is two groups of slots of unequal lengths with inclinations of 45° and 135° to the longitudinal axis of waveguides with the location of the centers of the slots on this axis. For the first option, it was proposed to improve the quality of frequency characteristics by increasing the number of slots, and by changing their location for the second option. Optimization result for 40 dB coupling with inclined slots for the full waveguide bandwidth: coupling accuracy is ±0,26 dB, coupling frequency sensitivity is ±0.12 dB, minimum directivity is 28 dB. For a 40 dB coupling in the form of longitudinal slots, these characteristics are respectively as follows: ±0,1 dB, ±0.54 dB, 26 dB. Based on the consideration of coupling options and coupling values, it is concluded that it is advisable to use waveguide counter-directional couplers with inclined slots and with coupling values of 35…60 dB in transmission lines measuring the passing power. The 30 dB coupling requires an increase in the length of two central slots, at which the ends of the slots converge. This leads to a decrease in the directivity of the coupler. Reducing the angle between the inclined slots and increasing the distance between the centers of the slots adds a few decibels of directivity. However, the characteristics are worse than the 40 dB coupler: ±0,26 dB, ±0.45 dB, 18.5 dB. The calculations were performed using electrodynamics modeling programs.

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