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The section of waveguide A-B carries a series arm C and a shunt arm D forming a bridge. Since waveguide dimensions are such that only the dominant mode propagates, the electric field in D is always normal to that in C. If symmetrically placed, there is no direct transmission between arms D and C. The very small amount of direct transmission between C and D caused by imperfections is represented by the directivity of the the hybrid tee. Power applied to either A or B divides equally between C and D, and none emerges from the opposite arm. If arms A and B terminate in |
matched loads, power entering C or D divides equally
between arms A and B. When the tee is used as a reflectometer, a signal generator is connected to arm C, a detector to arm D, and the system to be tested to arm A. The signal from C splits at the junction. The portion in arm B is terminated by the internal matched load. The portion in arm A is transmitted to the system to be tested. The signal reflected by the system under test again splits at the junction, but this time, between arms C and D. The signal in arm C is terminated by the signal generator, while that in arm D is coupled to the detector and associated display equipment. |