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I am trying to design UHF quadrature couplers from the following references:
[1] 'Broad-Band Twisted-Wire Quadrature Hybrids' , http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1127996
[2] 'Twisted wire Quadrature Hybrid Directional Couplers' QST Vol 63 January 1978 pages 21-23
[3] https://awrcorp.com/download/kb.aspx?file=VHF_Lump_Coupler.pdf
Schematic diagram here :
http://www.seboldt.net/k0jd/TwPQH.gif
and here:
http://c15_manali.tripod.com/hybrid.htm
This circuit needs a 1:1 transformer that should ideally have a coupling factor of 1. In practice, coupling factors above 0.7 seem to work reasonably well.
My question is about estimating the coupling factor from information on the wire diameters, separation, and twist. Now, the characteristic impedance of the twisted pair can be estimated from equations, e.g.:
http://qucs.sourceforge.net/tech/node93.html
Is there a way to relate the characteristic impecance to the coupling factor, e.g. by using the basic equations on series / parallel coupled inductors with aiding / opposing connections ?
[1] 'Broad-Band Twisted-Wire Quadrature Hybrids' , http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1127996
[2] 'Twisted wire Quadrature Hybrid Directional Couplers' QST Vol 63 January 1978 pages 21-23
[3] https://awrcorp.com/download/kb.aspx?file=VHF_Lump_Coupler.pdf
Schematic diagram here :
http://www.seboldt.net/k0jd/TwPQH.gif
and here:
http://c15_manali.tripod.com/hybrid.htm
This circuit needs a 1:1 transformer that should ideally have a coupling factor of 1. In practice, coupling factors above 0.7 seem to work reasonably well.
My question is about estimating the coupling factor from information on the wire diameters, separation, and twist. Now, the characteristic impedance of the twisted pair can be estimated from equations, e.g.:
http://qucs.sourceforge.net/tech/node93.html
Is there a way to relate the characteristic impecance to the coupling factor, e.g. by using the basic equations on series / parallel coupled inductors with aiding / opposing connections ?
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