Abstract: An antenna apparatus includes: a circuit board that has a main surface and a rear surface opposite to each other; an antenna element that is formed of a metal plate and is arranged at a predetermined distance from the main surface of the circuit board; a plurality of legs that extend from the antenna element toward the circuit board; a ground conductor that is formed on the main surface or the rear surface of the circuit board; a feeding pin that supplies power from the circuit board to the antenna element; and a plurality of comb-shaped capacitor patterns that are formed on one of or both the main surface and the rear surface of the circuit board and are electrically connected between the plurality of legs and the ground conductor.

Abstract: To provide a circularly polarized antenna capable of obtaining an excellent axial ratio over a very wide range and having a great gain in a zenith direction. The circularly polarized antenna (10) includes a planar loop antenna element (122) and feeding means for providing quadruple feeds with their phases varied by 90 degrees with respect to the planar loop antenna element (122). The feeding means has four feeding probes (131 through 134). The circularly polarized antenna (10) is provided with a circuit board (25) disposed in parallel with the planar loop antenna element (122). The circuit board (25) has an area greater than that of the planar loop antenna element (122). The circuit board (25) has a principal surface (25U) which entirely serves as a ground plane. The circuit board (25) has a rear surface (25L) provided with a 90-degree phase shifter formed thereon.

Abstract: An antenna apparatus includes: a circuit board that has a main surface and a rear surface opposite to each other; an antenna element that is formed of a metal plate and is arranged at a predetermined distance from the main surface of the circuit board; a plurality of legs that extend from the antenna element toward the circuit board; a ground conductor that is formed on the main surface or the rear surface of the circuit board; a feeding pin that supplies power from the circuit board to the antenna element; and a plurality of comb-shaped capacitor patterns that are formed on one of or both the main surface and the rear surface of the circuit board and are electrically connected between the plurality of legs and the ground conductor.

Abstract: In a loop antenna including a circuit board, a cylindrical body standing on a surface of the circuit board, and a loop antenna element formed on the cylindrical body along the peripheral surface, a tubular insulator member is placed with some space around the cylindrical body. A conductor ring is formed on the tubular insulator member along the peripheral surface, and is placed on an intermediate position between the surface of the circuit board and the plane formed by the loop antenna element. A conductor wall is placed with some space around the cylindrical body on an intermediate distance between the surface of the circuit board and the plane formed by the loop antenna element into height.

Abstract: In a loop antenna including a circuit board, a cylindrical body standing on a surface of the circuit board, and a loop antenna element formed on the cylindrical body along the peripheral surface, a tubular insulator member is placed with some space around the cylindrical body. A conductor ring is formed on the tubular insulator member along the peripheral surface, and is placed on an intermediate position between the surface of the circuit board and the plane formed by the loop antenna element. A conductor wall is placed with some space around the cylindrical body on an intermediate distance between the surface of the circuit board and the plane formed by the loop antenna element into height.

Abstract: In an electromagnetic coupling type four-point feeding loop antenna (10) comprising a tubular body (11), a loop portion (12) having a loop width (W1), four feeders (13) each having a feeder width (W2), and four electromagnetic coupling wires (17) each having a coupling wire width (W3), the loop width, the feeder width, and the coupling wire width are substantially equal to one another. A gap (&dgr;) between the feeder and the electromagnetic coupling wire is laid in a range between 0.2 mm and 0.8 mm, both inclusive, when the electromagnetic coupling type four-point feeding loop antenna has a feeding impedance of a range between 25 &OHgr; and 100 &OHgr;, both inclusive.

Abstract: A composite antenna apparatus includes a cylindrical member 4 formed by a flexible insulating film rolled into a cylindrical shape, a plurality of antenna patterns 3 formed in a helix pattern on a peripheral surface of the cylindrical member 4, a circuit board 2 fixed to one axial end of the cylindrical member 4 and having a circuit pattern 10 connected to the antenna patterns 3 by soldering, and a monopole antenna 1 disposed inside the cylindrical member 4 and standing up on one surface of the circuit board 2. The circuit board 2 is provided with a first metallic pattern 8 having a predetermined area and formed on the one surface of the circuit board 2 at a position inside the cylindrical member 4.

Abstract: In an electromagnetic coupling type four-point feeding loop antenna (10) comprising a tubular body (11), a loop portion (12) having a loop width (W1), four feeders (13) each having a feeder width (W2), and four electromagnetic coupling wires (17) each having a coupling wire width (W3), the loop width, the feeder width, and the coupling wire width are substantially equal to one another. A gap (&dgr;) between the feeder and the electromagnetic coupling wire is laid in a range between 0.2 mm and 0.8 mm, both inclusive, when the electromagnetic coupling type four-point feeding loop antenna has a feeding impedance of a range between 25 &OHgr; and 100 &OHgr;, both inclusive.

Abstract: A composite antenna apparatus includes a cylindrical member 4 formed by a flexible insulating film rolled into a cylindrical shape, a plurality of antenna patterns 3 formed in a helix pattern on a peripheral surface of the cylindrical member 4, a circuit board 2 fixed to one axial end of the cylindrical member 4 and having a circuit pattern 10 connected to the antenna patterns 3 by soldering, and a monopole antenna 1 disposed inside the cylindrical member 4 and standing up on one surface of the circuit board 2. The circuit board 2 is provided with a first metallic pattern 8 having a predetermined area and formed on the one surface of the circuit board 2 at a position inside the cylindrical member 4.

Abstract: In a monopole antenna having a monopole standing up on one surface of a circuit board, a metal case is provided on the other surface of the circuit board. The monopole and the metal case are covered with an exterior case. The metal case includes a base plate portion faced to the circuit board with a space kept therefrom, a side surface portion extending from a circumferential or peripheral edge of the base plate portion toward the circuit board and fixed to the circuit board, and a belt-like metal plate disposed outside the side surface portion and extending in the circumferential direction. The belt-like metal plate has a part which forms a wave-like shape of a wave traveling in the circumferential direction and is press-fitted between the side surface portion and the exterior case.