| 摘要 |
PROBLEM TO BE SOLVED: To provide an LNB which is improved in isolation and shield performance and also has cost advantages. SOLUTION: A multi-layered substrate 2 which has a thin substrate 2a as a 1st layer and a thick substrate 2b as a 2nd layer is arranged in the rear part of a feed horn 1, a ground pattern 5 is formed on both the surfaces of the 1st-layer substrate except the part corresponding to the rear opening part 1b of the feed horn, and a tube axis conductor 6 is formed at a tube axis part 1c of the feed horn; and receiving probes 7 and 7' which receive a horizontal polarized wave and a vertical polarized wave are formed on a part of a inner surface corresponding to the opening part, a nearly columnar conductor 9 is formed by connecting the tube axis conductor to a back solid pattern 8 of the 2nd-layer substrate through a through hole, and the both-sided ground pattern of the 1st-layer substrate and the back solid pattern of the 2nd-layer substrate are connected by a through hole along the rear opening peripheral edge of the feed horn to form a waveguide 10.
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