627 results about "Helical antenna" patented technology

The invention discloses a helical antenna with a small reflection surface, aiming at improving the helical antenna gain, enlarging the launching coverage range of a launcher and meeting the long-distance communication requirement of a tire pressure monitor system (TPMS). The helical antenna comprises a body and the reflection surface, wherein the body has a spiral structure formed by winding a metal wire or a metal tube, and is a normal mode helical antenna; and the reflection surface is arranged under the body and is connected with a negative pole or a ground wire of a feeding point of the body. The reflection surface meets the condition that (D0-D) / 2 is more than or equal to A-x and less than or equal to A, wherein D is the screw diameter of the body, D0 is the diameter of the reflection surface, A and x are constants, x is more than 0 and less than A, A is more than x and less than or equal to 0.01 lambda, and lambda is the wavelength of a signal transmitted by the launcher within the free space.

In a helical antenna apparatus, a first variable capacitance element is connected between a first helical antenna element and a second helical antenna element, and a second variable capacitance element is connected between a first terminal of a balanced port of a balanced to unbalanced transformer and the first helical antenna element. A third variable capacitance element is connected between a second terminal of the balanced port of the balanced to unbalanced transformer and the second helical antenna element. A detector measures a detection voltage Vd corresponding to a reflected power of a reflected signal reflected from the first and second helical antenna elements when the first and second helical antenna elements are fed with a transmission signal from a radio transmitter, and an adaptive controller adaptively controls respective capacitance values of the first to third variable capacitance elements.

Disclosed are extraction device and method utilizing a microwave coal heating layer. The extraction device mainly comprises an extraction and drainage pipe (1), a helical antenna (7), a front-loaded cover (6), a cable (8), a microwave generator (9), a controller (10), a cooling device (11), a gas exhaust pipe (12) and the like. The problems of low extraction rate and extraction speed of existing extraction methods are solved. The extraction method is characterized by including: firstly drilling a hole at an appointed position of an extraction coal layer, paving an anchorage net on the surface of the extraction coal layer and drilling a drill rod to reinforce the coal layer; placing the extraction and drainage pipe with the helical antenna into the drilled hole by the distance 0.6-1.0m away from the coal layer, sealing the hole by high-temperature-resistant cement grouting, and starting the microwave generator to heat the extraction coal layer to the temperature of 80-200 DEG C. After the coal layer is heated, desorption speed of gas is increased, the free gas is increased to cause increase of gas volume of the coal layer, so gas pressure is increased and gas extraction rate of gas of the coal layer in the negative-pressure extraction drilled hole is increased favorably.

Provides an antenna for a radio telephone whereby, in a state wherein the rod-shaped antenna is extended to outside the case of the radio telephone, the effects of the human body are negligible and emission of radio waves at an angle close to the horizontal direction is possible, and in a state wherein the rod-shaped antenna is retracted within the case, no unwanted radiation is produced. For this purpose, a helical antenna 20 having an electrical length of lambd / 4 and a rod-shaped antenna 10 extendable and retractable with respect to the case through the hollow central portion of the helical antenna 20 and having an electrical length of about 3lambd / 8 and inductive reactance are electrically coupled by means of an electrostatic coupling portion 30 having capacitive reactance such that, in the state wherein the rod-shaped antenna 10 is extended from the case 50, the inductive reactance of the rod-shaped antenna 10 is cancelled out. The length of the bottom portion 12a of the connecting member 12 is set to a length such that when the rod-shaped antenna 10 is retracted within the case 50, the bottom portion 12a of the connecting member 12 passes through the helical coil 12 over the entire length thereof, severing electrical coupling between the helical antenna 20 and the rod-shaped antenna 10.

A microwave antenna assembly including an elongated cooling jacket having proximal and distal ends and an inner lumen defined therebetween and a helical microwave antenna member disposed within at least a portion of the elongated cooling jacket and having an inner and outer conductor, the inner conductor disposed within the outer conductor, wherein at least a portion of the inner conductor extends distally from the outer conductor and forms at least one loop; and wherein the inner conductor is configured to deliver microwave energy.

Communications occur between a satellite and respective first and second classes of terminals using substantially different polarizations. The first class of terminals may include fixed and / or vehicle-based terminals, and the second class of terminals may include handheld terminals. The second class of terminals may include terminals configured to preferentially receive and / or transmit linearly polarized signals, for example, terminals with substantially linearly polarized antennas, and the first class of terminals may include terminals configured to preferentially receive and / or transmit circularly polarized signals, for example, terminals with patch and / or helical antennas configured to transmit and / or receive substantially circularly polarized signals.

In a helical antenna comprising a hollow cylindrical member having an inner peripheral surface and an outer peripheral surface and an antenna pattern film wound around the outer peripheral surface of the hollow cylindrical member, the helical antenna further comprises a center rod coaxial with a center axis of the hollow cylindrical member and at least three ribs disposed between the center rod and the inner peripheral surface of the hollow cylindrical member. The ribs symmetrically extends in a radial manner at equal angular intervals. The hollow cylindrical member, the center rod, and the ribs preferably may be integrally molded out of plastic. The antenna pattern film may comprise a flexible insulator film and a conductive pattern formed on the flexible insulator film. The conductive pattern has at least one antenna lead member which is wound around the outer peripheral surface of the hollow cylindrical member in a helix fashion.

The invention provides methods and apparatuses for a helical antenna assembly that are constructed by placing a metallic tape strip diagonally onto non-metallic tape. The tape assembly is then rolled on a dielectric core. The metallic tape strip is coupled to an electrical connector and a center conductor that is located through the center of the dielectric core. The tape assembly may include one or two tabs that are bent over the ends the dielectric core to prevent the tape assembly from separating from the dielectric core. The tabs may be pinned by eyelets that are affixed to the center conductor. The pitch of the conductive portion of the tape assembly is determined to provide desired electrical characteristics when the tape assembly is wrapped around the dielectric core. The conductive portion of the tape assembly may be trimmed to obtain desired electrical characteristics.

A quadrifilar helical antenna comprising two pairs of filars having unequal lengths and phase quadrature signals propagating thereon. A conductive H-shaped impedance matching element matches a source impedance to an antenna impedance. The impedance matching element having a feed terminal at the center thereof from which current is supplied to the two filars of each filar pair disposed about an edge of the impedance matching element and symmetric with respect to a center of the impedance matching element. The impedance matching element further comprises a reactive element for matching the antenna and source impedances.