AEL Power divider ( Arbitrary Termination Impedance, Arbitrary Power Division ) 유지호

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

AEL Necessity of the power divider power combining in phase or out of phase

AEL Large size at UHF or VHF band. 2.Designed to match 50 Ohm termination. ( Additional matching networks are necessary. - Increase system size ) 3.Symmetry -> Only equal power division ratio. Problems of conventional power dividers

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

AEL Size reduction technique (1) –> MTT-Trans (1991) A-A’ : symmetrical axis ring hybrid’ scattering matrix 1.Find S-parameter 2.Isolation : S 31 =S 42 =0 at f=f 0 3.3dB output power division -> |S 21 |=|S 41 | & |S 12 |=|S 32 | Then, obtain

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

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

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

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

AEL Arbitrary termination impedances (1) –> MTT-Trans (1999) Excitation at port 2 (V) (1)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,

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

AEL 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

AEL 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. 1.The two waves must have a phase shift of 180degree against each other, -> 2.The wave ratio must be b2 : b1 as shown left. Reciprocal 하므로 m=n=p=k & b1:b2=1:1 => conventional ring hybrid

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

AEL 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

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