GB1240860A - Improvements in or relating to electromagnetic wave filter units - Google Patents

Abstract

1,240,860. Microwave filters. SIEMENS A.G. 11 Oct., 1968 [12 Oct., 1967], No. 48259/68. Heading H1W. A microwave comb-type filter is realized by printing a conductive pattern of resonant sections on one side of an insulating sheet having a conductive ground plane on the opposite side, the pattern being connected to the ground plane at requisite earthing points by contacts extending through the sheet, the construction being completed by a second ground plane spaced from the conductive pattern on the side remote from the first ground plane. The second ground plane may be carried by a second conductive sheet having a conductive pattern and ground contacts which are a minor image of those carried by the first sheet, the two sheets co-operating to form a "sandwich line" construction. Various patterns are shown in the Figures. The line sections 1, Fig. 1b may be unconnected and earthed at alternate ends by contacts 2. The line sections 11, Fig. 2b, are all connected at one end to an earth strip 14 (dots indicate earthing contacts) and an earthed screening member 15 is arranged to screen the narrow end-portions of the lines from each other. The broad portions are coupled together inductively. Alternatively, a capacitative coupling between unconnected line sections may be used (Fig. 2c). The band-stop filter of Fig. 3 comprises resonant line sections 21 in a staggered arrangement on either side of a through strip 22.