DIRECTIONAL COUPLER, HIGH FREQUENCY TRANSMITTER-RECEIVER USING IT, RADAR APPARATUS, VEHICLE LOADED WITH RADAR APPARATUS, AND SMALL-SIZED SHIP LOADED WITH RADAR APPARATUS

摘要

PROBLEM TO BE SOLVED: To solve the problem that directivity and return loss become small when the size of a coupling hole is increased in order to increase a coupling degree in a conventional directional coupler provided with the coupling holes at the interval of the odd number multiple ofλg/4.

SOLUTION: In the directional coupler provided with the plurality of coupling holes 3 connecting both waveguides 1 and 2 on a guide wall between the waveguides 1 and 2 arranged adjacently to each other, when the intra-guide wavelength of the waveguides is defined asλg and the change of the phase angle of a transmission coefficient by the provision of one coupling hole 3 is defined asΔp(rad), the center interval of the plurality of coupling holes 3 is turned to ä(2n-1)/4+Δp/π}λg (n is a positive integer).

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