2. Briefly explain the operating principles of a two-opening superimposed- waveguide directional coupler. 3. Briefly explain...

  

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2. Briefly explain the operating principles of a two-opening superimposed- waveguide directional coupler. 3. Briefly explain what are the main parameters used to compare directional couplers: the coupling factor and the directivity. 4. What would be the directivity of an ideal directional coupler? 5. (Refer to Figure 48.) Determine the power at arms 2, 3 and 4 (P2, P3, and P4) if the incident power at arm 1 (P) is 1 mW, given a coupling factor C of 20 dB, and a directivity D of 20 dB. MATCHED LOAD CRUCIFORM OPENINGS (Ag/4 APART) LOWEN (MAIN) GUIDE UPPER (SECONDARY) GUIDE (ISOLATED ARM) Figure 48. Construction of the cross-guide directional coupler. Cruciform openings are preferred to circular openings because the discontinuity caused by a cruciform is smaller than that caused by a circle for the same degree of coupling. 2. Briefly explain the operating principles of a two-opening superimposed- waveguide directional coupler. 3. Briefly explain what are the main parameters used to compare directional couplers: the coupling factor and the directivity. 4. What would be the directivity of an ideal directional coupler? 5. (Refer to Figure 48.) Determine the power at arms 2, 3 and 4 (P2, P3, and P4) if the incident power at arm 1 (P) is 1 mW, given a coupling factor C of 20 dB, and a directivity D of 20 dB. MATCHED LOAD CRUCIFORM OPENINGS (Ag/4 APART) LOWEN (MAIN) GUIDE UPPER (SECONDARY) GUIDE (ISOLATED ARM) Figure 48. Construction of the cross-guide directional coupler. Cruciform openings are preferred to circular openings because the discontinuity caused by a cruciform is smaller than that caused by a circle for the same degree of coupling.