Abstract: A wire antenna for circularly polarized wave has a loop conductor that is composed of an outer element 3a of one turn and an inner element 3b of three-fourths turn. The antenna has an overall length of approximately 7/4 wave length and is a 7/4 turn loop of a rectangular shape with opposite ends separated. Feeding terminals 2a and 2b as feeding points are positioned at one turn point of the loop conductor.

Abstract: A microstrip antenna comprises a dielectric plate having a thickness to be sufficiently shorter than a free space wavelength, a rectangular radiation conductive plate member mounted on one surface of the dielectric plate and set to be constructed that each side ranges from 1/4 of guide wavelength through 1/2 of guide wavelength, and a pair of opposed parts each of which is extended from each side of the rectangular radiation conductive plate member and each side of parts is less than 1/4 of guide wavelength.

Abstract: A rod antenna includes extensible elements electrically connected to a high frequency power supply member. A low pass filter has one terminal connected to the extensible elements and the other terminal connected to a low frequency power supply member.

Abstract: An antenna device is comprised of a base member fixed to an automobile body, a first mast member, a second mast member and a third mast member. The third mast member is supported by the base member, the second mast member is supported by the third mast member and includes a plurality of telescopic elements and the first mast member is supported by one end of the second mast member and located away from the automobile body. A feeder conductor is connected to the first mast member through an impedance matching coil with the feeder conductor and the coil being molded in a resin elevation member. The resin elevation member extends through the second and third mast members and has an enlarged portion which surrounds the coil. The enlarged portion of the resin elevation member is in engagement with the second mast member and elevates the second mast member upon movement away from the automobile body.

Abstract: A microstrip antenna device for circularly polarized waves includes a dielectric sheet member, one surface of which has a radiating conductor sheet member while the opposite surface has a ground conductor sheet member. Denoting a point where a segment of a line passing through a geometrical center o, o of the radiating conductor sheet member intersects with the substantial periphery of the radiating conductor sheet member by a and denoting a point where the segment intersects with the substantial periphery of the ground conductor sheet member by b, the ratio of the length between the points o and b to the length between the points o and a should be at least equal to 1.5. Where rectangular radiating and ground conductor sheet members are used, a good circular polarization is achieved without any disturbance in the radiating pattern when the diagonal ratio of the respective members is equal to or greater than 1.5.

Abstract: A microstrip antenna has a rectangularly-shaped radiation conductive plate attached to one side of a dielectric plate, with a grounding conductive plate being attached to the other side of the dielectric plate. Rectangular line loads extend from adjacent sides of the radiation conductive plate. With such a configuration, the antenna retains all of the advantages of a microstrip antenna, including light weight, compactness, ease of manufacture, and a low profile, while enabling operation at multiple frequencies (four, on one embodiment), or polarization at multiple frequencies (two, in another embodiment).

Abstract: A high frequency amplifier is mounted in the immediate vicinity of a feeder of a microstrip antenna. A microstrip antenna includes a dielectric member and a grounded conductor member which is applied thereto. A second dielectric member is disposed on the side of the grounded conductor member which faces away from the dielectric member, and the high frequency amplifier is mounted on the surface of the second dielectric member which faces away from the grounded conductor member, and is connected to the feeder of the microstrip antenna. A transmission distance between the feeder and the high frequency amplifier, which represents an initial amplifier stage, is greatly reduced, thus drastically reducing disturbances caused by external noises and improving the noise figure of a receiving equipment.