EMLAB Directional couplers 1

EMLAB 7.4 Waveguide directional coupler Waveguide two-hole coupler Input Through Coupled Isolated 2

EMLAB Figure 7.4 (p. 313) Two commonly used symbols for directional couplers, and power flow conventions. 3

EMLAB Port 1 Port 2 Transfer switch Source B R A S-Parameter Test Set DUT FwdRev Directional coupler Application : network analyzer 4

EMLAB Waveguide multi-hole coupler 5

EMLAB 7.5 Quadrature hybrid coupler 6 ① ② ④ ③

EMLAB Even-odd mode analysis 7 Line of symmetry I=0 V=max ① ② ④ ③ ① ② ④ ③ Line of anti-symmetry I = max V = 0 ① ② ④ ③

EMLAB 8

9

Even mode analysis 10 Line of symmetry I=0 V=max Open circuited stubs ① ② ④ ③ ① ② ④ ③

EMLAB 11 ① ②

EMLAB GND via Odd mode analysis 12 Short-circuited stubs Line of anti-symmetry I=max V=0

EMLAB 13 ① ② Total scattered voltage

EMLAB 7.6 Coupled line coupler Coaxial coupler Microstrip coupler 14

EMLAB Even-odd mode analysis 15

EMLAB Even mode analysis 16

EMLAB Odd mode analysis 17

EMLAB 18 Total voltage 를 0 으로 만들기 위해라는 제약 조건 도입.

EMLAB Coupled Isolated Design of couple line coupler 19

EMLAB Freq. response of couple line coupler 20

EMLAB ° hybrid coupler 180° phase difference Sum, difference 21

EMLAB Figure 7.44 (p. 354) Even- and odd-mode decomposition of the ring hybrid when port 1 is excited with a unit amplitude incident wave. (a) Even mode. (b) Odd mode ° hybrid coupler 22

EMLAB Even mode analysis 23

EMLAB Odd mode analysis 24

EMLAB Figure 7.45 (p. 356) Even- and odd-mode decomposition of the ring hybrid when port 4 is excited with a unit amplitude incident wave. (a) Even mode. (b) Odd mode. 25

EMLAB Ring hybrid modulator 26

EMLAB 27