(19)

(11)

EP 0 526 457 A1

(12)

(43) Date of publication: 10.02.1993 Bulletin 1993/06 (21) Application number: 91903855.0 (22) Date of filing: 06.02.1991

(51) International Patent Classification (IPC):  H01Q 13/ 08( . ) H01Q 19/ 00( . ) H01Q 9/ 04( . ) H01Q 21/ 06( . ) (86) International application number: PCT/GB1991/000185 (87) International publication number: WO 1991/012637 (22.08.1991 Gazette 1991/19)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IT LI LU NL SE (30) Priority: 06.02.1990 GB 19900002636 (71) Applicant: BRITISH TELECOMMUNICATIONS public limited company London EC1A 7AJ (GB)	(72) Inventors: STAKER, Mark Robert Ipswich, Suffolk IP2 0XF (GB) MILLER, Paul Andrew Ipswich, Suffolk IP9 1RR (GB) MACKICHAN, John Cameron Felixstowe, Suffolk IP11 7NP (GB) (74) Representative: Buttrick, Richard, et al  British Telecommunications plc Intellectual Property Department 13th FLoor 151 Gower Street London WC1E 6BA London WC1E 6BA (GB)