EP 0772254 A1 19970507 - A combined duplex filter and antenna
Title (en)
A combined duplex filter and antenna
Title (de)
Kombiniertes Duplexfilter und Antenne
Title (fr)
Filtre duplex combiné et antenne
Publication
Application
Priority
FI 955302 A 19951106
Abstract (en)
The invention relates to a combined structure of an antenna (1) and a duplex filter (2b), in which said antenna (1) at its input point is connected directly to the duplex filter (2b) at an antenna connection point. Then it is not possible that an exceptional situation would occur, in which no radiating element would be connected to the duplex filter, for instance due to a damaged antenna, to the replacement action of a replaceable antenna, or due to an retractable antenna being in a position between the extreme positions. This prevents the transmit signal from reflecting at a high power level to the receive branch (RX), so that the receive branch (RX) can be dimensioned for a much lower power level that earlier, and it can utilize for instance current surface acoustic filters (7). Further the transmission line losses between the duplex filter and the antenna are minimized, and a filter designer is provided with the possibility to design the impedance of the duplex filter at its antenna connection point (3) so that it is directly matched to the input impedance of the antenna. <IMAGE>
IPC 1-7
IPC 8 full level
H01Q 1/24 (2006.01); H01Q 21/30 (2006.01)
CPC (source: EP)
H01Q 1/244 (2013.01); H01Q 21/30 (2013.01)
Citation (search report)
- [XY] GB 2271487 A 19940413 - MAXON SYSTEMS INC [GB]
- [X] EP 0259129 A2 19880309 - NEC CORP [JP]
- [A] US 4792939 A 19881220 - HIKITA MITSUTAKA [JP], et al
- [A] WO 9005390 A1 19900517 - MOTOROLA INC [US]
- [YA] IKATA O ET AL: "DEVELOPMENT OF SMALL ANTENNA DUPLEXER USING SAW FILTERS FOR HANDHELD PHONES", PROCEEDINGS OF THE ULTRASONICS SYMPOSIUM, BALTIMORE, OCT. 31 - NOV. 3, 1993, vol. 1, 31 October 1993 (1993-10-31), LEVY M;MCAVOY B R, pages 111 - 114, XP000473550
Designated contracting state (EPC)
CH DE FR GB LI
DOCDB simple family (publication)
EP 0772254 A1 19970507; EP 0772254 B1 20030312; DE 69626599 D1 20030417; DE 69626599 T2 20040205; FI 110556 B 20030214; FI 955302 A0 19951106; FI 955302 A 19970507
DOCDB simple family (application)
EP 96307644 A 19961022; DE 69626599 T 19961022; FI 955302 A 19951106