| 摘要 |
<p>A multi-port microwave coupler has six input ports In 1, In 2, In 3, In 4, In 5 and In 6 and six output ports Out 1, Out 2, Out 3, Out 4, Out 5 and Out 6 and is synthesised from nine 2 x 2 90 DEG hybrid couplers which are arranged as three sets, that is a first set A, B and C, a second set D, E and F and a third set G, H and I. A first group of transmission lines 11, 12, 13, 14, 15 and 16 interconnect the first and second sets of hybrid couplers, and a second group of transmission lines 21, 22, 23, 24, 25 and 26 interconnect the second and third sets of hybrid couplers. The first and third sets of couplers each give a 3dB power reduction, but the second set give a 1:2 power split between their outputs. Three 90 DEG phase shift devices X, Y and Z correct the phase of the signals in the transmission lines 21, 25 and 24 respectively. When equal amplitude signals are applied to all of the input ports, the combined signal can be directed to any one of the output ports by appropriately selecting the respective phases of the input signals. The first and second groups of transmission lines can be arranged as respective transmission rings so that all cross-overs in the transmission lines are avoided thereby providing a planar realisation of a 6 x 6 multi-port microwave coupler. The invention is of application to higher order n x n multi-port microwave couplers where n = 2<p> x 2<q> with both p and q as whole numbers. <IMAGE></p> |
