(19)

(11)

EP 0 888 645 A1

(12)

(43) Date of publication: 07.01.1999 Bulletin 1999/01 (21) Application number: 97908392.0 (22) Date of filing: 19.03.1997

(51) International Patent Classification (IPC):  H01P 1/ 20( . ) (86) International application number: PCT/GB1997/000786 (87) International publication number: WO 1997/036339 (02.10.1997 Gazette 1997/42)

(84) Designated Contracting States: AT BE CH DE DK ES FI FR GB GR IE IT LI NL PT SE (30) Priority: 23.03.1996 GB 19960006178 (71) Applicant: Filtronic PLC Saltair, Shipley BD18 3TT (GB)	(72) Inventors: RHODES, John Filtronic plc The Waterfront Saltair Shipley BD18 3TT (GB) HUNTER, Ian Filtronic plc The Waterfront Shipley BD18 3TT (GB) (74) Representative: Orr, William McLean  Urquhart-Dykes & Lord, Tower House, Merrion Way Leeds LS2 8PA Leeds LS2 8PA (GB)