619 results about "Helical antenna" patented technology

A circular-polarization dipole helical antenna is used for electronic device and satellite terminal and includes a base, and an antenna conductor arranged on surface of the base. The antenna conductor includes a plurality of metal conductors with high Q value and anti-oxidation property and continuously and helically coated on surface of the base. The base is made of low loss and high dielectric constant material. An unbalance-to-balance circuit module connects two signal-feeding ends to the base with phase difference of 180 degree. The problems of narrow bandwidth, low efficiency, complicated structure and precise manufacture can be solved.

An apparatus and method for enabling far-field radio-frequency communications with an implantable medical device in which an antenna is embedded within a dielectric compartment of the device. A helical antenna may be employed to save space while still permitting far-field telemetry over a desired range of frequencies.

A helical antenna has a helix supported by a helix support. The helix support includes at least one piece of flexible sheet having its two surfaces covered with a layer antistatic material. The flexible sheet is curlable into a revolution surface configuration to form a revolution surface-shaped support section for at least partially supporting a portion of the helix component there around. A grounding mechanism electrically grounds the external sheet surface to the helix and the two sheet surfaces to one another when in the revolution surface configuration while a locking mechanism locks the flexible sheet in the revolution surface configuration. The combination of the helix and the flexible support renders the antenna structurally relatively rigid in all directions.

A helical antenna having a central axis defined between a base end and a distal end comprises a helical conductor wound about the central axis and having a feed line disposed at the base end and along the central axis, and may also include an elongated dielectric core about which the electrical conductor is wound.

A dielectrically-loaded loop antenna with a cylindrical dielectric core, a feeder structure passing axially through the core, a sleeve balun encircling one end portion of the core and helical antenna elements extending from a feed connection with the feeder structure at the other end of the core to the rim of the balun. The antenna elements are arranged as a pair of laterally opposed groups of conductive elongate helical elements each having at least first and second conductive elements of different electrical lengths to form a plurality of looped conductive paths. By forming at least one of the conductive elements in each group as a conductive strip with one or both edges meandered, such that the edges of the strip are non-parallel and have different electrical lengths, additional modes of resonance arc created, yielding an improvement in bandwidth.

A device for directing energy to a target volume of tissue includes a helical antenna assembly that includes a helical antenna radiating section having a helical antenna element. The helical antenna assembly is capable of operating in at least one of a first mode of operation for directing energy to a first portion of the target volume of tissue and a second mode of operation for directing energy to a second portion of the target volume of tissue.

A multi-band helical antenna of the present invention includes a dielectric body including a plurality of dielectric sheets stacked in a predetermined order and a first and a second metallic pattern sections provided in the dielectric body. The first metallic pattern includes a plurality of first partially opened metallic loop patterns and a plurality of first connection elements connecting the respective adjacent first partially opened metallic loop patterns to form a first spiral structure. The second metallic pattern section includes a plurality of second partially opened metallic loop patterns and a plurality of second connection elements connecting the respective adjacent second partially opened metallic loop patterns to form a second spiral structure. The first and the second metallic pattern sections having different entire lengths. Accordingly, the multi-band helical antenna of the present invention has a dual resonant frequency characteristic and operates in different frequency bands.

An electrically small broadband antenna comprises a plurality generalized contrawound toroidal helical antenna elements, each made from a single continuous conductor divided into two length portions each of which are substantially the same length and which have a generalized helical pattern, wherein the helical pitch senses the two length portions are opposite to one another, and the two length portions are insulated from one another and overlap one another on the surface of a generalized toroid. Each antenna element incorporates a signal coupler with an impedance matching network, wherein the first ports of the plurality of signal couplers are in proximate location to one another and are connected together to a common signal input port, and the second ports of the respective signal couplers are connected to the respective signal feed ports at the node locations where the respective length portions join one another, or at a diametrically opposite location.

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.

An electromagnetic surgical ablation probe having a tunable helical antenna element is disclosed. The probe includes a coaxial feedline having an inner conductor coaxially disposed within a dielectric, and an outer conductor coaxially disposed around the dielectric. The inner conductor and dielectric extend distally beyond a distal end of the outer conductor. A helical antenna element is operably coupled to a distal end of the inner conductor. During use, the antenna may be tuned by changing at least one dimension of the helical antenna element. Embodiments are presented wherein a dimensions of the helical antenna element is changed by state change of a shape memory alloy, by a change in temperature, by activation of a piston by fluidic pressure, by linear motion of a conical tip, and by a manual screw-type adjustment.

A microstrip antenna (MSA) above a ground plane, having a size corresponding to an operation frequency, at a junction point thereof, electrically connected to one end of a monopole antenna having a size corresponding to the operation frequency to operate as a complex antenna. A distance between the feed point of MSA and the junction point determines the input impedance for matching. A microstrip line or an (planer) inverted-F antenna may provide the MSA. The monopole element may be a monopole antenna or helical antenna. A portable wireless communication apparatus includes the antenna apparatus having a housing. The monopole antenna is connected to the MSA when the monopole antenna is extended from the housing. A switch may be provided between the monopole antenna and the MSA for diversity operation. The antenna apparatus may be formed on a Printed circuit board and folded.

The present invention is to provide a combination antenna having multi-mode and multi-band arrangements, which comprises a conductive seat; a non-uniform helical antenna extending from one end of the conductive seat; and a pole antenna extending from one end of the conductive seat through the helical antenna, enabling to be tuned to three or more resonant frequencies through tuning the helical antenna to a plurality of resonant frequencies and tuning the pole antenna to a plurality of resonant frequencies different from that to which the helical antenna is tuned.

A mobile communication device has an antenna assembly comprising the combination of an inverted-F antenna and a dielectrically-loaded quadrifilar helical antenna, the latter mounted on the distal end of an elongate radiator element of the inverted-F antenna. The dielectrically-loaded antenna has an integral balun on a ceramic antenna core, the balun providing a balanced feed for the radiating elements of the antenna The elongate radiator structure of the inverted-F antenna acts as a feed path for the dielectrically-loaded antenna, the feed path extending along the elongate radiator structure from the balun to a ground connection element of the inverted-F antenna and, thence, to a signal port associated with a grounding connection of the inverted-F antenna Placing the dielectrically-loaded quadrifilar antenna at the end of the radiator structure of the inverted-F antenna rather than alongside the latter substantially reduces breakthrough from a transmitter coupled to the inverted-F antenna to receiving circuitry coupled to the dielectrically-loaded antenna.

A folded helical antenna. Generally, the inventive antenna includes plural radiating elements of conductive material. In the preferred embodiment, the antenna is a quadrifilar helix antenna having four radiating elements. Each radiating element is constrained into a helical shape. In accordance with the present teachings, each radiating element extends in a first direction and has a portion thereof folded in a second direction, the second direction being substantially parallel to the first direction. The novel method of making a quadrifilar helix antenna of the invention includes the steps of: ascertaining desired antenna characteristics for a given application; ascertaining limitations on antenna height for the application; fabricating a helical antenna in accordance with the desired antenna characteristics; and adjusting the height of the antenna in accordance with the limitations by folding the radiating elements thereof.

Objects containing radio frequency transponders, such as RFID tags, can be encoded with information and mixed with a substance. The mixed objects and substance can be applied to a surface such as a road, such that a vehicle traveling over the surface may later read encoded information stored in the transponders. In one variation, the objects may include spherical marbles that are mixed with asphalt and embedded in a road surface. An apparatus includes components arranged to receive multiple objects, encode transponders contained in the objects, and mix them with a substance such as asphalt or concrete. Objects may include spheres having helical antenna elements or antenna elements formed on an outer surface thereof. A vehicle may be configured with a reader and antennas arranged to read transponders embedded in a roadway surface.

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.