76 results about "Electrically small antenna" patented technology

An antenna consisting of a thin strip bent-wire monopole disposed on an artificial magnetic conductor (AMC) is loaded at the end opposite to the feed point with a distributed or lumped capacitance to achieve an electrically small antenna for use in handheld wireless devices. The capacitive load reduces the length of the antenna to smaller than one-quarter of a wavelength at a given frequency of operation without suffering a substantial loss of efficiency. This results in an easier integration into portable devices, greater radiation efficiency than other loaded antenna approaches and longer battery life in portable devices, and lower cost than use of a chip inductor.

A planar small antenna and a small strip radiator are provided which have increased bandwidth. The small strip radiator has a main strip pattern and a plurality of convoluted strip patterns terminating the main strip pattern at each end. The plurality of convoluted strip patterns are arranged in mirror-symmetrical arrangement with reference to the longitudinal axis of the main strip such that one pair of convoluted strip patterns is convoluted clockwise while another pair is convoluted counterclockwise. As a result, an electrically small antenna radiator requires less metal or conductive material than conventional radiators, and also can operate without adversely affecting the radiation characteristics of the antenna.

The invention relates to a broadband high-efficiency and high-directionality electrically small antenna, and belongs to the technical field of antennae. The antenna comprises an exciting unit, an upper parasitic unit, a lower parasitic unit, two thin cylindrical dielectric slabs and a coaxial feeder. The radii of the two thin cylindrical dielectric slabs are the same, the centers of the two thin cylindrical dielectric slabs are aligned, and the two thin cylindrical dielectric slabs are parallel in the vertical direction. The exciting unit and the upper parasitic unit are arranged on the bottom surface and the top surface of the upper thin cylindrical dielectric slab respectively, and the lower parasitic unit is arranged on the top surface of the lower thin cylindrical dielectric slab. An inner conductor and an outer conductor of the coaxial feeder are connected with two metal sheets of the existing unit respectively, and the feed end of the coaxial feeder penetrates through the lower thin cylindrical dielectric slab, extends to the lower side of the lower thin cylindrical dielectric slab by a certain distance and is connected with a 50 omega signal source. The antenna is simple in design, compact in structure and easy to manufacture and can be applied to broadband wireless communication systems with the operating frequency being 1 GHz or so.

A planar small antenna and a small strip radiator are provided which have increased bandwidth. The small strip radiator has a main strip pattern and a plurality of convoluted strip patterns terminating the main strip pattern at each end. The plurality of convoluted strip patterns are arranged in mirror-symmetrical arrangement with reference to the longitudinal axis of the main strip such that one pair of convoluted strip patterns is convoluted clockwise while another pair is convoluted counterclockwise. As a result, an electrically small antenna radiator requires less metal or conductive material than conventional radiators, and also can operate without adversely affecting the radiation characteristics of the antenna.

The invention discloses an optimum match design of an electrically small antenna broadband matching network and the electrically small antenna broadband matching network, wherein a R-C additional damping network in a broadband matching network structure is directly connected with an electrically small antenna in parallel, and the impedance of the antenna can be changed into a new mode, which not only improves the impedance characteristics of an antenna end port and also prominently lowers the comparison between a real part and an imaginary part of the electrically small antenna, and namely the impedance of the electrically small antenna is compensated to a certain extent, which enables the electrically small antenna to be matched easily. The broadband matching network is designed through adopting an optimum method which combines a real frequency method and a direct optimization method. A better matching network structure is obtained through changing and filtering measured data of the antenna impedance from the characteristics of the electrically small antenna, and then, the optimization characteristics of the optimization algorithm are utilized to obtain each element value in the matching network structure. The standing wave ratio of the electrically small antenna with the matching network structure of the invention is smaller than 25 in a pass band, and the efficiency is bigger than 30% simultaneously, which enables the performance of the electrically small antenna to be greatly improved.

An antenna system for reception of channel signals form the UHF band by a receiver, including an electrically small antenna and, connected between the port connected to the antenna and that of the receiver, an active impedance matching device controlled by command signals depending on the quality of the signal received by the receiver to compensate for the impedance variations due to the environment associated with the antenna and to reject the frequencies of interfering channels adjacent to the reception channel without interfering with the active impedance matching of the antenna.

A circuit for tuning a resonance frequency of an electrically small antenna. The circuit includes a first source configured for providing a modulation signal, a second source configured for providing a periodic electrical signal, an antenna, and a tuning circuit configured for modulating a resonance frequency of the antenna in response to the modulation signal. The tuning circuit includes first and second capacitors that are alternately coupled to the antenna to change the resonance frequency of the antenna. The capacitor currently coupled to the antenna is decoupled from the antenna and the other capacitor is coupled to the antenna when the voltage across the capacitor currently coupled to the antenna is momentarily zero. In an exemplary embodiment, the tuning circuit comprises first and second inductors rather than capacitors. The inductors are switched into and out of the circuit when the current through the currently coupled inductor is momentarily zero.

An electrically small antenna (ESA) for resolution of subwavelength features is disclosed. The ESA is on the order of meters and has an efficient transmit / receive capability. The ESA is 1 / 10 of the length of the equivalent dipole length, and may be scaled down to 1 / 10,000. The ESA includes a metamaterial shell. Such an antenna may include phase sensitive current injection in the metamaterial resonant structures for loss-compensation.

A directive electrically small antenna (DESA) process and method employs multipole synthesis to implement directive electrically small multipole antennas with ultra-wideband (UWB) stable antenna patterns. Although lossy, embodiments have adequate efficiency to work as receive antennas in the high ambient noise environment of the HF band and below. Employing a process dubbed “antenna regeneration,” energy may be circulated within an antenna by means other than resonance. This enables multiple decade UWB response without the efficiency penalties inherent to traditional resistively-loaded antenna systems. Regenerative antennas can simultaneously achieve the performance of high Q resonant antennas and the bandwidth of resistively loaded antennas.

An improved wireless radio-frequency (RF) transmission system is disclosed. The wireless RF transmission system comprises: 1) a radio frequency (RF) transceiver configured to transmit and receive radio-frequency signals; ii) an electrically small antenna having a complex impedance comprising a real part and an imaginary part; and iii) a tunable negative impedance converter (NIC) circuit coupling the electrically small antenna to the RF transceiver. The tunable NIC circuit is configured to perform antenna matching by reducing the imaginary part of the complex impedance of the electrically small antenna. The tunable NIC circuit is tuned by adjusting a transconductance value associated with the tunable NIC circuit.

Inductively coupled antennas and methods of designing the same are disclosed. Electrically small antennas having relatively high efficiency and relatively broad bandwidth may be formed by inductively coupling an antenna loop to at least one antenna winding. Such antennas may be substantially planar. Various operating characteristics of such antennas may be adjustable by and / or dependent upon the strength of the inductive coupling between an antenna winding and an antenna loop.

Multi-band antennae used for television reception of at least two different frequency bands enable multi-band reception with an electrically small antenna. The designs are applicable to individual antenna elements, two dimensional arrays, three dimensional arrays, and arrays constructed for high volumetric efficiency. By using the multi-band element, greater frequency reception is achieved with greater density possible in the antenna arrays.

A directive electrically small antenna (DESA) process and method employs multipole synthesis to implement directive electrically small multipole antennas with ultra-wideband (UWB) stable antenna patterns. Although lossy, embodiments have adequate efficiency to work as receive antennas in the high ambient noise environment of the HF band and below. Employing a process dubbed “antenna regeneration,” energy may be circulated within an antenna by means other than resonance. This enables multiple decade UWB response without the efficiency penalties inherent to traditional resistively-loaded antenna systems. Regenerative antennas can simultaneously achieve the performance of high Q resonant antennas and the bandwidth of resistively loaded antennas.

An antenna comprising: a driven element; an input feed coupled to the driven element wherein the input feed is configured to be connected to a receiver; a non-Foster circuit having a negative impedance, wherein the non-Foster circuit is configured to actively load the antenna at a location on the antenna other than at the input feed; and wherein the antenna fits within an imaginary sphere having a radius a, and wherein the product ka is less than 0.5, where k is a wave number.

An antenna system and related method are disclosed for an electrically small antenna of variable geometry capable of a harmonically pure resonant radiation pattern over a broadband coverage of frequency selection. One geometrical embodiment comprises a multiple loop antenna system is configured to radiate a switched signal via the multiple antenna elements to inhibit transmission of any of the harmonics of the signal. An additional geometrical embodiment comprises a cylindrical shell with one or more interior center conductors to overcome radiation resistance and radiate a signal pattern of desirable toroidal shape free from undesirable harmonics.

A RF signal test and measurement system capable of measuring forward and reverse signal parameters of RF components including Electrically Small Antennas (ESA) and capable of being integrated within a communications system to aid the automatic retuning of antennas.

An antenna system, with a loop antenna and a loop current, is provided for transmitting an electromagnetic signal through a medium. The loop antenna has an E field transducer that generates an E field, and an H field transducer that generates an H field. The E and H fields are orthogonal in space and have at least one of a magnitude and phase relationship that is matched to an intrinsic impedance of a medium to generate a propagating wave. In an insulating medium the loop current lags an E field plate voltage by 90° to produce in phase E and H fields. In a conductive medium current is applied to the loop with a 135° phase lag with respect to a voltage across the E field plates. The H field is generated by the current component and leads current by 90°.