GB1418675A - Distributed impedance transmission lines - Google Patents

Abstract

1418675 Microstrip lines RCA CORPORATION 8 Dec 1972 [9 Dec 1971 (2)] 56652/72 Heading H1W A microwave transmission line comprises two parallel conductive strips arranged on either side of a dielectric medium with non-corresponding longitudinal edges adjacent each other. Thus, as shown in Fig. 6, the line consists of a metallic strip 55 arranged on one side of a dielectric substrate 53 and a second, segmented, strip 61, 63, 65, 67 arranged on the other side. The edge 87 of strip 55 is adjacent the edges 79, 81, 83, 85 of the segments forming the second strip. In the modification of Fig. 8, strips 131, 133 are mounted on spaced substrates 135, 137. The characteristic impedance of the line does not depend upon the thickness of the dielectric between the strips but upon the degree of overlap or underlap of the adjacent edges. Fig. 6 illustrates methods of coupling the line to an ordinary microstrip line 76, to a slotline 72 and to a co-planar line 82. In the latter case, a conductive bridge 82A ensures that segments 63, 67, spaced from either edge of strip 65, are at the same potential. The various lines may form short-circuited or open-circuited stubs affording reactances of either sign in shunt or in series with the main line 55, 61, 63, 65, 67 (see Fig. 7, not shown).