Electronic means for switching antennas to a common bus

(19)

(11)

EP 0 410 725 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	29.05.1991 Bulletin 1991/22

(43)	Date of publication A2:
	30.01.1991 Bulletin 1991/05

(21)	Application number: 90308154.5

(22)	Date of filing: 25.07.1990

(51)	International Patent Classification (IPC)⁵: H01Q 3/24

(84)	Designated Contracting States:
	DE FR GB IT

(30)

Priority:

28.07.1989 US 386509

(71)	Applicant: MINNESOTA MINING AND MANUFACTURING COMPANY
	St. Paul, Minnesota 55133-3427 (US)

(72)	Inventor:
	Whittington,Mark, c/o Minnesota Mining and St. Paul, Minnesota 55133-3427 (US)

(74)	Representative: Baillie, Iain Cameron et al
	c/o Ladas & Parry Altheimer Eck 2 80331 München 80331 München (DE)

(56)

References cited: :

(54)	Electronic means for switching antennas to a common bus

(57) A circuit for selecting an input to a signal processing network from among several switchable antenna units. Each antenna unit (26) includes a winding (30) which is connected to a common signal bus. The switchable antenna units (12) may be placed in "on" or "off" states in response to a controller, such as a microprocessor (46). One terminal (36,40) of each winding (30,32) is connected to a transistor (42,48) which causes the terminal to be in an open condition when the unit is unselected, attenuating any signal which might otherwise be transmitted to the signal bus. A second winding (32) is inductively coupled to the first winding (32) and is used to improve attenuation of unselected signals.

Search report