Helical filter

Abstract

Abstract PURPOSE:To improve the precision of a coupling part and to reduce variance in characteristics, by constituting coupling elements with low input and output impedance in spiral printed patterns for tuning elements with extremely high impedance. CONSTITUTION:In a shield case 12 which has a partition plate 11 with a coupling window 10, coiled tuning elements 14 and 14' connected electrically in parallel to variable capacitors 13 and 13' are arranged, and a printed board 15 is coupled with the case 12. On the surface of this board 15, spiral patterns 16 and 16' constituting the tuning elements 14 and 14' partially are formed and on the reverse surface, strip lines 17 and 17' are formed as input and output lead- out lines. Then, the case 12 and board 15 are combined together. At the same time, tips of the tuning elements 14 and 14' are inserted into center holes 18 and 18' of the spiral patterns 16 and 16' and soldered, allowing the spiral pattern 16 and 16' and tuning elements 14 and 14' to tune to a passing band in one body. Consequently, the precision of the coupling part is improved and variance in characteristics is reduced.

Inventors

• 👤 Kunio Hibino
• 👤 日比野　邦夫

Bibliographic Details