(19)

(11)

EP 0 593 661 A1

(12)

(43) Date of publication: 27.04.1994 Bulletin 1994/17 (21) Application number: 92915853.0 (22) Date of filing: 13.07.1992

(51) International Patent Classification (IPC):  H01P 1/ 208( . ) (86) International application number: PCT/GB1992/001276 (87) International publication number: WO 1993/001626 (21.01.1993 Gazette 1993/03)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IT LI LU MC NL SE (30) Priority: 11.07.1991 GB 19910014971 (71) Applicant: FILTRONIC COMPONENTS LIMITED Charlestown Shipley West Yorkshire, BD17 7SW (GB)	(72) Inventors: POPPLETON, David, Martin 7 Dewhirst Road Baildon West Yorkshire BD17 6DW (GB) RHODES, John, David ''Boodles'', Thorpe Lane West Yorkshire LS28 1AB (GB) (74) Representative: Gibson, Stewart Harry  URQUHART-DYKES & LORD, Three Trinity Court, 21-27 Newport Road Cardiff CF2 1AA Cardiff CF2 1AA (GB)