MICROSTRIP TRANSMISSION LINE STRUCTURE AND UNEQUAL POWER DIVIDERS AND BRANCH HYBRID COUPLERS USING THE SAME

摘要

A microstrip transmission line structure and an unequal power divider and a branch hybrid coupler using the same are provided to achieve a variable division ratio by utilizing electrical characteristics of a DGS(Defected Ground Structure) through a dual microstrip dielectric substrate. A microstrip transmission line structure includes first and second dielectric substrates. The first dielectric substrate has a main body with a first surface and a second surface opposite to the first surface, a microstrip transmission line formed on the first surface, a ground layer formed on the second surface, and a DGS(164) formed on the ground layer in a size and a shape corresponding to the optimum characteristic impedance. The second dielectric substrate has a main body with a first surface and a second surface opposite to the first substrate, a second ground layer(173) formed on the second surface and a conductive layer(175) formed in a via hole passing through the main body. The second ground layer is electrically connected to the ground layer of the first dielectric substrate through the conductive layer. A first ground layer is formed on the first surface of the second dielectric substrate, overlapped with the ground layer including the DGS, and exposes some region of the first surface of the second dielectric substrate at a larger size than the DGS.