Abstract: A microwave data transmission apparatus adapted to transmit and receive information by microwaves, in which an identification tag is made smaller in size and lighter in weight to considerably improve the convenience in a setting operation for use in many applications. The apparatus can be applied for production control within a factory or can be used to recognize whether a person wearing an identification tag has entered or left a room.

Abstract: A microwave data transmission apparatus adapted to transmit and receive information by microwaves, which the identification tag is made smaller in size and lighter in weight to considerably improve the convenience in setting operation for use in many applications, can be applied for the production control within the factory or the control for entering and leaving the room by a person having an identification tag.

Abstract: The SSB modulator according to the present invention is comprised of a driving voltage generator, a diode, a bias supply circuit, an impedance transformation circuit and an input/output terminal. The SSB modulator is arranged such that the impedance of the diode is changed by changing the driving voltage impressed across the diode, resulting in the mismatching of the impedance, which leads to generation of a reflected wave. Therefore, by changing the amplitude and the phase of the above-obtained reflected wave, SSB modulation is effected. Accordingly, the SSB modulator of the present invention, requiring no particular side band filter, is compact in size, light in weight and low in manufacturing cost, with a simple structure of the circuit.

Abstract: An antenna system includes a reflector which is a part of a paraboloid of revolution or parabolic cylinder, a primary radiator for clockwise circularly polarized wave, and a primary radiator for counterclockwise circularly polarized wave. The reflector is of geometrically asymmetrical shape to effect different reflection properties for clockwise and counterclockwise circular polarizations. The primary radiators are fixed at two different positions in the vicinity of the focus of the paraboloid reflector.