Abstract: An optically transparent coplanar microwave slot antenna formed between a first glass layer and a second glass layer is provided including a metal oxide layer, a first slot element and a second slot element formed in a dipole arrangement within the metal oxide layer wherein the first slot element is formed by a first triangular slot, a first trapezoidal slot, and a first rectangular slot and the second slot element is formed by a second triangular slot, a second trapezoidal slot, and a second rectangular slot, and a waveguide feedline for carrying microwave signals to the first slot element and the second slot element.

Abstract: Antenna system includes a base structure and a multiplicity of vertebrae arranged in a stack to define a spine. The spine has an elongated length which extends from a base end to a tip end. A compression applicator is configured to apply an elastic compression force on the stack in a direction along the elongated length from the tip end to the base end. Vertebra interfaces associated with each of the adjacent pairs of the vertebrae are configured to facilitate a variable deviation in an angular alignment of a vertebra axis of each vertebra relative to an adjacent one of the vertebra contained in the stack.

Abstract: A bicone antenna and methods for manufacture therefor can include a feed portion, a top section and a bottom section that can be centered on a vertical axis. The top section and bottom sections can each have a respective conical surface, which can extend radially outward from the vertical axis at an inner portion at a constant angle ?1 with respect to a horizontal antenna axis of the antenna. For both sections, the inner portion can merge into an outer portion that can have a curved surface, with the curved surface extending radially outward from the conical surface so that the curved surface has a logarithmic profile when viewed in side profile. The above structure can allow for a multi-directional antenna with a minimum of moving parts, which can be easily manufactured, including by additive manufacturing techniques.

Abstract: A low-profile dual-band high-isolation antenna module is fixed on a substrate and includes two high-frequency antennas and two low-frequency antennas located on two opposite sides of the substrate respectively. The bottom ends of the low-frequency antennas are connected to a grounding of the substrate. A decoupling element is disposed between the high-frequency antennas and the low-frequency antennas. The top end of each high-frequency antenna forms a bent portion, and so does the top end of each low-frequency antenna. The decoupling element has two ends extending to positions corresponding respectively to the low-frequency antennas but is not in contact with the low-frequency antennas or the high-frequency antennas. The bottom end of the decoupling element is connected to the grounding through at least one metal strip. The bent portions effectively reduce the space occupied by the antennas while the decoupling element provides isolation between the antennas.

Abstract: Disclosed herein are polarization and frequency reconfigurable origami-folded antennas and methods for making the same. An origami-folded antenna can include at least one ground plane that can include a dielectric stratum and a conductive stratum that is at least partially disposed on the conductive stratum. The origami-folded antenna can further include at least two helical sections that can include a dielectric sheet and a conductive sheet. The origami-folded antenna can be expanded to an expanded state and compressed to a compressed state along a center axis, and the antenna can have a greater length along the center axis when in the expanded state than when in the compressed state.

Abstract: An antenna device includes a base plate, an opposing conductor plate, a short-circuiting portion, a power-feed point, and at least one second-frequency electric-field impeding element provided to the opposing conductor plate, the base plate, or between the opposing conductor plate and the base plate. The second-frequency electric-field impeding element impedes a propagation of an electric field being vertical to the base plate and heading from the short-circuiting portion toward an outer edge portion of the opposing conductor plate, is induced at a second frequency higher than the first frequency, does not impede a propagation of the electric field induced at the first frequency, and is disposed such that an electrical area of the opposing conductor plate for a signal at the second frequency is an area of a proper size to generate an electrostatic capacitance that undergoes parallel resonance with the inductance of the short-circuiting portion at the second frequency.

Abstract: A mobile terminal, where the mobile terminal includes an antenna, where the antenna includes a first radiator, a second radiator that forms an electrical connection with the first radiator, a first ground branch that forms a coupling part with one end of the first radiator, and a second ground branch that forms another coupling part with the other end of the first radiator, where the first radiator, the first ground branch, and the second ground branch form an outer frame of the mobile terminal, the second radiator encircles in an inner side of the outer frame formed by the first radiator, the first ground branch, and the second ground branch, and the first radiator and the second radiator generate resonances in different frequency bands.

Abstract: The invention relates to a vertical broadband monopole antenna for vehicles, for two frequency bands separated by a frequency gap, said antenna having a first capacity top and a further capacity top, which is capacitively coupled to the first capacity top, wherein the further capacity top has at least one inductive high-resistance conductive strip, which extends to a conductive ground surface and is conductively connected thereto at its lower end.

Abstract: A receiving antenna for wirelessly receiving data between a stator of a computed tomography (CT) imaging modality and a rotor of the CT imaging modality is provided. The rotor rotates about a rotational axis. The receiving antenna includes a dielectric portion and a conductive portion coupled to the dielectric portion. A second surface of the conductive portion extends between a first end and a second end along a conductive axis that is substantially perpendicular to the rotational axis. The second surface of the conductive portion has a first length at a first length location along a first length axis that is substantially parallel to the conductive axis. The second surface of the conductive portion has a second length at a second length location along a second length axis that is substantially parallel to the conductive axis. The first length is different than the second length.

Abstract: An antenna enables compact and robust multiband operation of portable radios. According to some embodiments, the antenna includes: a first rolled conductive strip having a first section with overlap between successive turns of the first conductive strip and a second section with no overlap between successive turns of the first conductive strip, the first section having an insulating layer between the overlapping successive turns of the first conductive strip; a second rolled conductive strip; and a flexible sheet to which both the first conductive strip and the second conductive strip are bonded.

Abstract: Disclosed is an antenna capable of operating at more than one frequency band. The antenna comprises a first main helix antenna element and a second parasitic helix antenna element electromagnetically coupled to integrate a single radiofrequency connection structure operating in dual frequency bands. Furthermore, the antenna is configured to structurally combine a plurality of helix antenna elements to operate at multiple frequency bands having only one radiofrequency connector.

Abstract: The present invention relates to a series fed collinear antenna which includes cone-shaped radiating elements energized via a series fed common transmission line. Phasing stubs are provided between selected radiating elements and are oriented such that the phasing stub improves gain and reliability by affecting the signal to produce a beneficial elevational coordinate signal pattern. A ground plane may be provided proximate the lower end of the antenna structure to further enhance the radiated signal. The ground plane may be formed in the shape of a dome having an apex vertically disposed above a rim.

Abstract: The present invention relates to a series fed collinear antenna which includes cone-shaped radiating elements energized via a series fed common transmission line. Phasing stubs are provided between selected radiating elements and are oriented such that the phasing stub improves gain and reliability by affecting the signal to produce a beneficial elevational coordinate signal pattern. The radiating elements may be cones. Each cone has an associated base diameter. The base diameter may be uniform, resulting in similarly sized cones, or a cone may have a distinct base diameter resulting in differently sized cone elements.

Abstract: An apparatus includes first and second antenna elements each having a tapered width end, with the tapered width ends being separated by a gap. A portion of the edge of the tapered width end of the each antenna element has a thickness less than a thickness of the remainder of the respective antenna element. Such portion may be the portion of the edge of the antenna elements closest to a feed point of the antenna elements, and may be angled to a point or a flat edge. The thickness of the tapered width ends increases along the width and/or the height of the respective antenna element as the antenna element extends from the feed point.

Abstract: A dual band antenna having a directive element and a reflective element is disclosed. A first and second antennas are arranged substantially parallel to each other and spaced between approximately 0.5-0.8 times the wavelength of the first antenna. The dual band antenna provides high gain at the zenith and at the horizon and enable v variation in the antenna beam shape as well as a reduction in cross polarization.

Abstract: An antenna comprises a medium substrate and grounding units attached on the medium substrate. The antenna further comprises a metal structure attached on the medium substrate. The metal structure comprises an electromagnetic response unit, a metal open ring enclosing the electromagnetic response unit and a feeding point connected to an end of the metal open ring. The electromagnetic response unit comprises an electric-field coupling structure. This design increases the physical length of the antenna equivalently, so an RF antenna operating at an extremely low frequency can be designed within a very small space. This can eliminate the physical limitation imposed by the spatial area when the conventional antenna operates at a low frequency, and satisfy the requirements of miniaturization, a low operating frequency and broadband multi-mode services for the mobile phone antenna. Meanwhile, a solution of a lower cost is provided for design of the antenna of wireless communication apparatuses.

Abstract: The panel type antenna includes a flat conductive mount including at least one orifice, at least one radiating element including a base mounted beneath a dipole and a device for coupling and fixing the radiating element to the support. The device for coupling and fixing the radiating element, comprising a base mounted beneath a dipole, on the support with a dielectric part including a base with a dimension greater than the orifice in the support, at least one rod joined with the base and extending in a direction perpendicular to the plane of the base through the orifice of the support adapted for the insertion of the rod, at least one protuberance built into the end of the rod able to cooperate with the radiating element to hold it in place. The device includes a dielectric layer between the radiating element and the conductive mount to avoid direct contact.

Abstract: An antenna assembly is provided, including a first radiative element. The first radiative element is oriented such that a first end of the radiative element is operatively connected to an antenna feed and at least a portion of the radiative element includes a first conical, helical coil. The first conical, helical coil reaches a maximum diameter at a point farthest from the antenna feed. A counterpoise structure includes one of an electrically conductive ground structure operatively connected to a ground associated with the antenna feed and a second radiative element operatively connected to the antenna feed and the first radiative element at the antenna feed.

Abstract: A partial discharge detection device for detecting and measuring partial discharges in electric systems or components, which delivers signals having a form much resembling that of the radiated pulse, for improved identification and analysis. The device is of small size, totally insulated and self-powered, and allows measurements to be performed with the highest safety with no need for direct connection, thereby allowing operators to stand at a distance and avoid any system shutdown while making measurements. Furthermore, it can also detect and deliver the sync signal, which is obtained by picking up the supply voltage of the discharge generating components.

Abstract: An antenna, a portable electronic device incorporating an antenna and a method of operation are provided. The antenna includes a first radiator extending from a first end configured to be coupled to radio frequency circuitry to a second end that is electrically open. The antenna also includes a second radiator extending from a first end that is configured to be grounded to a second end that is electrically open. The antenna is configured such that the second end of one of the first or second radiators is electrically coupled to the other of the first or second radiators at a coupling region between the first and second ends of the other of the first or second radiators. The second end of the second radiator may be electrically coupled to the first radiator at a location between the first and second ends of the first radiator.

Abstract: A dual mode ground penetrating radar includes an enclosure which houses radar electronics. The dual mode ground penetrating radar includes an enclosure housing radar electronics. The dual mode ground penetrating radar further includes a first antenna feed having ferrite loading and extending outside of the enclosure. The dual mode ground penetrating radar further includes a second antenna feed spaced apart from the first antenna feed, the second antenna feed having ferrite loading and extending outside of the enclosure. An RF signal is provided in at least one of the first and second antenna feeds by the radar electronics.

Abstract: A compact, omnidirectional, broadband biconical antenna is described, having a first segment with its tip coincident with a horizontal plane, with an elevation angle between 23 degrees and 30 degrees from the horizontal plane; an open second segment joined to a distal end of the first segment, an elevation angle approximately 30 degrees greater than the first segment angle; an open third segment joined to a distal end of the open second segment, an elevation angle approximately 30 degrees greater than the open second segment angle; an open fourth resistive film segment joined to a distal end of the open third segment, an elevation angle approximately equal to the open third segment angle, wherein the segments are mirrored to form a biconical antenna; and a transmission line coupled to the tip of the first segment, interior to the first segment.

Abstract: In an antenna and a semiconductor device including the antenna, an object is to reduce the distance between electrodes of a capacitor as much as possible, reduce the area of the electrode of the capacitor as much as possible, and prevent the suppression of response sensitivity and a response range of the semiconductor device. The present invention relates to an antenna including an antenna coil provided over a first region of a base and a capacitor which uses a second region of the base as a dielectric body and which has electrodes provided for opposite planes of the second region of the base, wherein the second region of the base is thinner than the first region of the base, and also relates to a semiconductor device including the antenna.

Abstract: An IC tag can be mounted without deteriorating appearance of a container, breakage or the like of the IC tag can be prevented and excellent wireless communication between a reader/writer becomes possible by eliminating influence of the metal container by ensuring a long communication distance to the reader/writer by allowing excellent communication properties to be exhibited even when an existing IC chip is used and mounting an insulated and sealed IC tag on a metallic cover having a low possibility of being brought into contact with other goods and equipment and being hidden by the adjacent metallic containers. The metallic cover is provided with an IC chip (41), which has a pull-tab (33), and an IC tag (40) for the IC chip (41) mounted on the tab (33), an antenna for the IC tab (40) and a matching circuit (50) for matching impedances between the antenna and the IC chip.

Abstract: An antenna device includes: an antenna base plate having a shape of a flat plate; a capacity loading plate of a top capacity loaded type monopole antenna, the capacity loading plate arranged in parallel with the antenna base plate; and a planar antenna arranged between the antenna base plate and the capacity loading plate. A size of at least a part of the capacity loading plate in a direction of width of the capacity loading plate is less than about ¼ wavelength of receiving frequency of the planar antenna, and edges of the capacity loading plate in the direction of width of the capacity loading plate are folded back so that the capacity loading plate has a meander shape extending in a direction of length of the capacity loading plate.

Abstract: A multi-band antenna includes a ground plane, a branch active element connected to the ground plane, and a plurality of parasitic coupling elements connected to the ground plane. Respective ones of the parasitic coupling elements are electrically coupled to the branch active element such that the multi-band antenna resonates at a plurality of frequency bands.

Abstract: A Frequency Agile Electrically Small Tactical AM Broadcast Band Antenna System (NC#098978) comprising a transmitter, antenna, plurality of mast wires and configurable tophat assembly. The transmitter is designed to transmit radio frequency signals. The antenna tuning unit is operatively coupled to the transmitter and designed to tune the apparatus to a desired frequency. The plurality of mast wires operatively is coupled to the antenna tuning unit and designed to receive and output radio frequency signals. The configurable tophat assembly is operatively coupled to the plurality of mast wires. The configurable tophat assembly comprises a tophat disc comprising a conductive material, a plurality of tophat wires comprising a conductor material and a plurality of tophat jumpers designed to help configure said plurality of tophat wires to different lengths by providing electrical open and electrical short states.

Abstract: The present invention relates to an antenna device for a portable radio communication device adapted for receiving and/or transmitting radio signals in at least a first and a second operating frequency band, said antenna device comprising a half-loop radiating element, comprising a feeding portion and a grounding portion, and arranged to operate at FM frequencies. The antenna device comprises a capacitor at said feeding portion and an inductor at said grounding portion, and said half-loop radiating element is arranged to simultaneously with FM frequencies operate at frequencies at least ten times higher than FM frequencies, wherein said capacitor is arranged to short circuit said half-loop radiating element to ground for frequencies at least ten times higher than FM frequencies and said inductor is arranged to short circuit said half-loop radiating element to ground for FM frequencies.

Abstract: Antenna embodiments are illustrated that are particularly suited for use in aircraft navigation, identification and collision avoidance systems. An exemplary antenna embodiment operates about a center wavelength and in association with a ground plane and comprises first and second grounded, shortened, and top loaded monopoles. These monopoles are spaced apart above a ground plane and each of them includes a feed post, a shorted post, and a top load wherein the shorted post is spaced from the feed post, is coupled to the ground plane, and has a length less than one fourth of the center wavelength. In addition, the top load is coupled to the feed post and the shorted post and is configured along orthogonal minor and major axes of the top load to have a width along the minor axis and a length along the major axis that exceeds the width.

Abstract: A top load multi-band monopole antenna is utilized with an integrated resonator to achieving broad band and multiband performance for multiple frequency spectrums. The top loaded monopole antenna can utilize a low frequency band (e.g., approximately 700/800/900 MHz) and a high frequency band (e.g., approximately 1900 MHz to approximately 1500 MHz) by implementation of the resonator. The resonator matches an impedance of the upper portion of the top loaded monopole antenna for capabilities in a high frequency range without interference from any low frequency range.

Abstract: A novel loaded antenna is defined in the present invention. The radiating element of the loaded antenna consists of two different parts: a conducting surface and a loading structure. By means of this configuration, the antenna provides a small and multiband performance, and hence it features a similar behavior through different frequency bands.

Abstract: When first and second housings are in an open state, first and second switches are electrically opened, and thus, a first antenna element and a ground conductor operate as a first dipole antenna, and a second antenna element and the ground conductor operate as a second dipole antenna with isolation from the first dipole antenna by the slit. When the first and second housings are in the closed state, the first and second switches are electrically closed, and thus, the first antenna element operates as a first inverted F antenna on the ground conductor, and the second antenna element operates as a second inverted F antenna on the ground conductor with isolation from the first inverted F antenna by the slit.

Abstract: A narrow band, tunable antenna uses a series of small inductors wired in series to produce different resonant frequencies from a single antenna across a wide frequency spectrum. Radio Frequency (RF) switches are positioned in parallel with the inductors and are capable of shunting a selected inductor out of the antenna circuit thereby changing the electrical length of the antenna and consequently, the resonant frequency. The RF switch control circuitry is isolated from the RF current in the antenna.

Abstract: An antenna assembly is provided, including a first radiative element. The first radiative element is oriented such that a first end of the radiative element is operatively connected to an antenna feed and at least a portion of the radiative element includes a first conical, helical coil. The first conical, helical coil reaches a maximum diameter at a point farthest from the antenna feed. A counterpoise structure includes one of an electrically conductive ground structure operatively connected to a ground associated with the antenna feed and a second radiative element operatively connected to the antenna feed and the first radiative element at the antenna feed.

Abstract: A multiband antenna includes a feed portion, a radiating portion, and a ground via. The feed portion includes a first feed section and a second feed section paralleled to each other. The radiating portion includes a first radiator, a second radiator and a third radiator. The first radiator is L shaped with a free end. The second radiator is L shaped with a free end. The free ends of the second radiator and the first radiator extend toward to each other and partially overlap to define a slot therebetween. The third radiator includes a trapezoid section and a connecting section. The short portion includes a first short section and a second short section. The first short section connects the first radiator to the ground via, and the second short section connects the second radiator and the third radiator to the ground via.

Abstract: A multi-band antenna includes a ground plane, a branch active element connected to the ground plane, and a plurality of parasitic coupling elements connected to the ground plane. Respective ones of the parasitic coupling elements are electrically coupled to the branch active element such that the multi-band antenna resonates at a plurality of frequency bands.

Abstract: The present invention relates to an antenna device for a portable radio communication device adapted for receiving and/or transmitting radio signals in at least a first and a second operating frequency band, said antenna device comprising a half-loop radiating element, comprising a feeding portion and a grounding portion, and arranged to operate at FM frequencies. The antenna device comprises a capacitor at said feeding portion and an inductor at said grounding portion, and said half-loop radiating element is arranged to simultaneously with FM frequencies operate at frequencies at least ten times higher than FM frequencies, wherein said capacitor is arranged to short circuit said half-loop radiating element to ground for frequencies at least ten times higher than FM frequencies and said inductor is arranged to short circuit said half-loop radiating element to ground for FM frequencies.

Abstract: In an antenna that has high sensitivity to frequencies of narrow bands and over a wide band and that can be small-sized, and in a wireless module, wireless unit and wireless apparatus using this antenna, the antenna is comprised of a transmission line, and variable capacitance means connected to this transmission line, and the variable capacitance means controls the resonant frequency.

Abstract: A broadband antenna system includes a ground plane, a metal plate parallel to the ground plane, and constituting a capacitance load against the ground plane, and a radiation structure connected perpendicularly to the ground plane and the metal plate. The radiation structure includes a feed conductor to supply an electric signal, a short-circuit stub to transfer the supplied electric signal to the ground plane, a conducting bridge to interconnect the feed conductor and the short-circuit stub, which is separated from the metal plate, and a radiating conductor connected to the ground plane the metal plate, and coupled to the supplied electric signal to thereby radiate electromagnetic waves.

Abstract: A dual autodiplexing antenna (300) redirects power flow (303) from an unloaded antenna to a loaded antenna, thereby improving communication performance under loaded conditions. The dual autodiplexing antenna (300) includes a first antenna (101) disposed at a first end (103) of a portable two-way communication device (100). A second antenna (102) is disposed at the distal end (104) of the portable two-way communication device (100). The first antenna (101) and second antenna (102) are coupled to a transceiver (107) by a first transmission line matching circuit (201) and a second transmission line matching circuit (202), respectively. In one embodiment, the first antenna (101) is configured to primarily operate in a first bandwidth, while the second antenna (102) is configured to primarily operate in a second bandwidth. When one of the first antenna (101) or second antenna (102) is loaded, power flow (303) is redirected to the lesser loaded antenna.

Abstract: Compact top-loaded, fractal monopole antenna system embodiments are provided for multi-band airborne operation over ultrabroadband ranges (e.g., 30 to 2000 MHz). These multi-band embodiments are self-contained, aerodynamic and compact (e.g., blade height less than 9.5 inches) and are power efficient with a low return loss (e.g., less than ?7 dB). System embodiments include a set of impedance-matching circuits configured to substantially match an antenna impedance to a predetermined system impedance over a set of predetermined frequency bands. In an embodiment, at least one impedance-matching circuit includes a chain of selectable air-core inductors which are novelly arranged to improve radiation efficiency and prevent damage to support substrates. In an embodiment, a lowest-frequency one of the impedance-matching circuits is configured to process signals having a maximum wavelength ?max wherein a fractal member is configured with a length that does not exceed ?max/40.

Abstract: The present invention encompasses an antenna (12) for use with a radio-frequency identification transponder (10) that performs optimally in free space and near optimally when near a conductive surface. The radio-frequency identification transponder (10) broadly comprises an antenna (12); an integrated circuit (14); a matching circuit (16) interposed between the antenna (12) and integrated circuit (14); and a substrate (18). The antenna (12) is designed with a length so the antenna (12) as a microstrip resonates at a starting frequency and a matching circuit is constructed. The antenna (12) is placed near a conductive surface and the length of the antenna is adjusted until the antenna reactance is approximately the opposite of the integrated circuit reactance.

Abstract: A novel loaded antenna is defined in the present invention. The radiating element of the loaded antenna consists of two different parts: a conducting surface and a loading structure. By means of this configuration, the antenna provides a small and multiband performance, and hence it features a similar behavior through different frequency bands.

Abstract: A novel loaded antenna is defined in the present invention. The radiating element of the loaded antenna consists of two different parts: a conducting surface and a loading structure. By means of this configuration, the antenna provides a small and multiband performance, and hence it features a similar behavior through different frequency bands.

Abstract: A broadband antenna system includes a ground plane, a metal plate parallel to the ground plane, and constituting a capacitance load against the ground plane, and a radiation structure connected perpendicularly to the ground plane and the metal plate. The radiation structure includes a feed conductor to supply an electric signal, a short-circuit stub to transfer the supplied electric signal to the ground plane, a conducting bridge to interconnect the feed conductor and the short-circuit stub, which is separated from the metal plate, and a radiating conductor connected to the ground plane the metal plate, and coupled to the supplied electric signal to thereby radiate electromagnetic waves.

Abstract: A novel loaded antenna is defined in the present invention. The radiating element of the loaded antenna consists of two different parts: a conducting surface and a loading structure. By means of this configuration, the antenna provides a small and multiband performance, and hence it features a similar behaviour through different frequency bands.

Abstract: A planar antenna able to secure a wide frequency band and having high reliability. Therefore, the planar antenna has at least a grounding plate, a radiating conductor, a matching portion, a power supply portion, a spacer, a central conductor and a coaxial connector. The matching portion is a flat plate having a taper shape (an inverse taper shape) narrowed in width from the power supply portion to the radiating conductor. Further, the matching portion is slantingly arranged with respect to the grounding plate.

Abstract: A novel loaded antenna is defined in the present invention. The radiating element of the loaded antenna consists of two different parts: a conducting surface and a loading structure. By means of this configuration, the antenna provides a small and multiband performance, and hence it features a similar behaviour through different frequency bands.

Abstract: In an exemplary aspect of the invention, an antenna is disclosed that includes a ground plane and a disk disposed adjacent to the ground plane. The disk has a perimeter. The antenna further includes a loading reflector having an underside. At least a portion of the underside is electrically connected to a portion of the perimeter of the disk. The loading reflector has a width at a widest point, and the width at the widest point of the loading reflector is larger than a thickness of the disk. The disk may be circular or elliptical. The ground plane may include a cavity, where the disk is disposed within an outer border of the cavity. When an elliptical disk is used, the cavity may also be elliptical. An elliptical cavity may have a parabolic surface.

Abstract: A planar antenna has a radiating element and a ground plate. A body of a vehicle has an internal edge that is formed by making a hole in the body. The planar antenna is located in the hole so that an imaginary plane of the internal edge is located between the radiating element and the ground plate. In such a structure, electric lines of force perpendicularly pass through the body beside the planar antenna. As a result, electric fields are maintained in the vertical direction even if the planar antenna is mounted on the vehicle. This maintains a horizontal directivity of the planar antenna.