Abstract: A multi-antenna system for differential wireless communication devices, such as transceivers, transmitters or receivers, includes a wireless communication device having a differential port including first and second nodes and a common ground for an antenna connection; a first antenna connected between the first node and the common ground; and a second antenna connected between the second node and the common ground.

Abstract: The operation of a mobile communication apparatus is enhanced particularly in the lower frequency portion of its bandwidth by connecting an electrically-conductive ground-enlarger to the electrically-conductive ground of the printed wired board (PWB) containing the communication circuitry such that the ground-enlarger effectively enlarges the ground of the PWB to load the antenna in the lower portion of its radio frequency band. The ground-enlarger may include stub ground-enlarger integrally formed on the PWB, or connected thereto, preferably at the end of the PWB opposite to that connected to the antenna. The antenna may be an internal antenna or an external antenna.

Abstract: The operation of a mobile communication apparatus is enhanced particularly in the lower frequency portion of its bandwidth by connecting an electrically-conductive reflector to the electrically-conductive ground of the printed wired board (PWB) containing the communication circuitry such that the reflector effectively enlarges the ground of the PWB to load the antenna in the lower portion of its radio frequency band. The reflector may include stub reflectors integrally formed on the PWB, or connected thereto, preferably at the end of the PWB opposite to that connected to the antenna. The antenna may be an internal antenna or an external antenna.

Abstract: A multi-band microwave antenna which is resonant and radiant at a high frequency band and at one or more lower frequency bands includes an electrically-conductive ground plane on one face of a dielectric substrate; an electrically conductive strip line on the opposite face of the dielectric substrate; a curved slot formed in the ground plane having a feed side electromagnetically coupled to the feed end of the strip line, and a load side electromagnetically coupled to the load end of the strip line, such that the slot is resonant and radiant at the high frequency band; and a further electrical conductor electrically connected to the ground plane to serve as a continuation thereof at the load side of the slot and electromagnetically coupled to the slot at the lower frequency bands such as to cause the slot to be resonant and radiant also at the lower frequency band or bands.

Abstract: A printed circuit board having foamed substrates of low dielectric constant and low dissipation factor and techniques for making printed circuit boards and printed circuits using such substrates. The substrate has a dielectric constant less than 1.5 and a dissipation factor less than 10.sup.-2, most preferably, polymethylacrylimide. A conductive layer is placed on the substrate surface using chemical deposition or by use of appropriate adhesives. The printed circuit may be imprinted by conventional techniques such as etching with appropriate etching materials.

Abstract: A broadband microwave antenna exhibiting high radiation efficiency over a broad frequency band in which the VSWR is less than 2.5:1 over at least 15% of the frequency band, includes a ground plane at one side of a dielectric substrate and formed with at least one slot, and a feed strip at the other side of the substrate. The feed strip is of uniform width for substantially its complete length, but includes a change in width at the feed end of the slot to produce a first impedance matching network effective to bring the slot impedance to the level of the feed line over the broad frequency band, and another change in width at the load end of the slot to produce a second impedance matching network which reduces the slot reactance to match the reactive impedance of the load to the reactive part of the slot impedance over the broad frequency band.