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Power divider ( Arbitrary Termination Impedance, Arbitrary Power Division )

Power divider ( Arbitrary Termination Impedance, Arbitrary Power Division ). 2004-21566 유지호. Contents. Necessity of the power divider Problems of conventional power dividers Size reduction technique Arbitrary termination Impedance technique Arbitrary power division technique

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Power divider ( Arbitrary Termination Impedance, Arbitrary Power Division )

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  1. Power divider ( Arbitrary Termination Impedance, Arbitrary Power Division ) 2004-21566 유지호

  2. Contents • Necessity of the power divider • Problems of conventional power dividers • Size reduction technique • Arbitrary termination Impedance technique • Arbitrary power division technique • Conclusion

  3. Necessity of the power divider power combining in phase or out of phase

  4. Problems of conventional power dividers • Large size at UHF or VHF band. • Designed to match 50 Ohm termination. ( Additional matching networks are necessary. - Increase system size ) • Symmetry -> Only equal power division ratio.

  5. Size reduction technique (1) –> MTT-Trans (1991) A-A’ : symmetrical axis ring hybrid’ scattering matrix Isolation

  6. Size reduction technique (1) –> MTT-Trans (1991) A-A’ : symmetrical axis ring hybrid’ scattering matrix • Find S-parameter • Isolation : S31=S42=0 at f=f0 • 3dB output power division • -> |S21|=|S41| & |S12|=|S32| • Then, obtain

  7. Size reduction technique (1) –> MTT-Trans (1991) 3dB power division & good matching

  8. Size reduction technique (2) –> MTT-S (1989) BUT -> 1. series L : high resistive losses 2. Same termination impedances

  9. Size reduction technique (3) –> MTT-Trans (1994) 1 : Input 2 : +90 output 4 : -90 output 3 : isolation 1 : Input 2 : +90 output 4 : -90 output 3 : isolation series L : 3개 series L : 1개 Reduce series L

  10. Size reduction technique (3) –> MTT-Trans (1994) Remove series L (1980 ) But limited to equal-power split-ring hybrid

  11. Arbitrary termination impedances (1) –> MTT-Trans (1999) • Excitation at port 2 (V) • Transmission line Eq • node 1&2, node 3&1 • (2)node Eq • node 1, node 2, node 2&GND, nod 2&3 • (3)3dB power division • (4) So determine optimum load (1) ~ (4) Then,

  12. Arbitrary termination impedances (1) –> MTT-Trans (1999) Power division & isolation matching

  13. Arbitrary power division & termination impedances (2) –> MTT-Trans (1997) Lossless -> 3 port isolation & 1 port matched -> S31=0 & excitation for port 1 & put wave ratio = b1 : b2 = S21 : S41 Under the assumption S31=0, the characteristic admittances Y1, Y4 determined

  14. Arbitrary power division & termination impedances (2) –> MTT-Trans (1997) • excitation for port 3 • The dummy arms Y2 and Y3 makes port 2&4 isolation • If isolation is not ideal -> small power flows forward to port 3 • For these two waves to be isolated from port 1, two conditions must be satisfied. • The two waves must have a phase shift of 180degree against each other, • -> • The wave ratio must be b2 : b1 as shown left. • Reciprocal 하므로 m=n=p=k & b1:b2=1:1 => conventional ring hybrid

  15. Arbitrary power division & termination impedances (2) –> MTT-Trans (1997) Port 1 : n=1 -> 50 Ohm Port 2 : m=1.1 -> 45.45 Ohm Port 3 : p=0.7 -> 71.429 Ohm Port 4 : k=0.8 -> 62.5 Ohm Power spilt ratio : 2dB ( 20log(b1/b2) =2dB ) Simulation Result S21=-2.124dB , S41=-4.124dB S43=-2.124dB , S23=-4.124dB S31=-158..656dB , S42=-160.656dB Power division Isolation matching

  16. Conclusion • Power divider’s size may be reduce • ( less than quarter wave line, • & lumped element ) • We can remove matching network with Arbitrary termination Impedance & Arbitrary power division power divider. • -> realize small size system

  17. References • Three-Port 3-dB Power Divider Terminated by Different Impedances and Its Application to MMIC’s , IEEE MTT Trans. 1999 • Arbitrary Termination Impedances, Arbitrary Power Division, and Small-Sized Ring Hybrids, IEEE MTT Trans. 1997 • Miniaturized 3-dB ring hybrid terminated by arbitrary impedances, IEEE MTT Trans. 1994 • Design of new hybrid-ring, directional coupler using λ/8 or λ/6 sections, IEEE MTT Trans. 1991 • 180° lumped element hybrid, IEEE MTT-S.1989

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