Patent ID: 6545640
Filing Date: 2003-04-08
Classification: H01Q

Abstract:
A two-band transmission system including:a signal processor adapted to be tuned in two operating bands centered on respective predetermined center frequencies to transmit and/or receive an electrical signal in each of the two bands, a microstrip antenna, and an antenna connection system including electrical conductors connecting the processor to the antenna for coupling said electrical signal to radiated waves, wherein the antenna includes: a conductive ground plane, a conductive patch having a periphery, an electric substrate positioned between said conductive ground plane and said conductive patch, a short-circuit formed at said periphery, and a separator slot having an origin consisting of an opening in said periphery, said slot penetrating said patch from said origin, wherein said short-circuit and said separator slot enable two resonances to be established in said antenna, one of said two resonances is of the quarter-wave type with an at least virtual electric field node fixed by said short-circuit, constitutes a primary resonance and has a primary frequency substantially equal to one of said two center frequencies, and the other of said two resonances constitutes a secondary resonance having a secondary frequency substantially equal to the other of said two center frequencies, and wherein said electrical conductors of the connection system include said ground plane and a main antenna coupling conductor which is part of said patch to enable said antenna to be coupled to said signal processor around each of said two center frequencies, which transmission system is characterized in that said separator slot extends in said patch as far as a rear end of said slot located at a sufficiently small distance from said periphery for said slot to divide said patch partly into a body including said main antenna coupling conductor and said short-circuit and a tail free of said short-circuit and electrically connected to said connection system only by means of said body and a passage consisting of an area of said patch between a back and said periphery.