Showing papers on "Feed line published in 2013"

Wireless Transmission with Channel State Perturbation

Abstract: Generating a channel codebook by identifying a subset of antenna configurations from a plurality of antenna configurations of an antenna associated with a transmitter by: transmitting a sequence of symbols from the transmitter to a receiver using the plurality of antenna configurations, wherein each antenna configuration provides a unique transmission characteristic to the receiver; receiving feedback from the receiver that identifies the subset of antenna configurations; and, generating channel codebook entries corresponding to the subset of antenna configurations; and, transmitting data from the transmitter to the receiver using the channel codebook.

Reconfigurable single and multi-sector cell site system

Abstract: A telecommunications system is provided that is controllably operable as a sectorized antenna system and as an omnidirectional antenna system without requiring hardware reconfiguration. The telecommunications system includes a phase correlation measurement unit that can be between a sectorized antenna sub-system and a remotely located RF source site. The phase correlation measurement unit can be coupled to the RF source site over at least one feed line. The phase correlation measurement unit can ouptut signals for controlling a phase shifter at the RF source site for phase shifting downlink signals and for causing operation of the sectorized antenna sub-system as an omnidirectional antenna sub-system. In a sectorized operation mode, the phase correlation measurement unit and the phase shifter can be inactivated.

Multiple Band-Notched UWB Antenna With Band-Rejected Elements Integrated in the Feed Line

Abstract: To mitigate potential interferences with coexisting wireless systems operating over 3.3-3.6 GHz, 5.15-5.35 GHz, or 5.725-5.825 GHz bands, four novel band-notched antennas suitable for ultra-wideband (UWB) applications are proposed. These include UWB antennas with a single wide notched band, a single narrow notched band, dual notched bands, and triple notched bands. Each antenna comprises a half-circle shaped patch with an open rectangular slot and a half-circle shaped ground plane. Good band-notched performance is achieved by using high permittivity and low dielectric loss substrate, and inserting quarter-wavelength horizontal/vertical stubs or alternatively embedding quarter-wavelength open-ended slots within the feed line. The results of both simulation and measurement confirm that the gain suppression of the single and multiple band-notched antennas in each desired notched band are over 15 dB and 10 dB , respectively. The radiation pattern of the proposed triple band-notched design is relatively stable across the operating frequency band.

Control of Higher Harmonics and Their Radiations in Microstrip Antennas Using Compact Defected Ground Structures

Abstract: Controlling higher order modes up to third harmonic of the fundamental operating frequency in a microstrip line-fed patch antenna has been successfully demonstrated. Harmonic rejection in the antenna has been achieved at its feed level using highly compact design of defected ground structure (DGS). Rejection characteristics have been improved adding an open stub to the feed line. All possible higher order modes occurring in between the fundamental and the 3rd harmonic have been identified. Relative suppression of radiated fields with and without DGS-control has been quantitatively measured and effective control of harmonics has been experimentally ensured. The area occupied by the proposed DGS has been compared with earlier designs and over 40-90% reduction in size has been documented.

Active antenna system (AAS) radio frequency (RF) module with heat sink integrated antenna reflector

Abstract: On-board heat dissipation can be achieved in radio frequency (RF) modules by integrating a heat sink into the RF module's antenna reflector. Said integration achieves a compact and aesthetically pleasing RF module design that reduces the overall footprint of modular active antenna systems (AASs). Embodiment antenna reflectors include portions that are perforated and/or exposed to free flowing air to provide enhanced heat dissipation capability.

Antennas for standard fit hearing assistance devices

Abstract: An embodiment of a hearing assistance device comprises a housing, a power source, a radio circuit, an antenna and a transmission line. The radio circuit is within the housing and electrically connected to the power source. The antenna has an aperture, and the radio circuit is at least substantially within the aperture. The transmission line electrically connects to the antenna to the radio circuit. Various antenna embodiments include a flex circuit antenna.

Dual Circularly-Polarized Patch Antenna Using Even and Odd Feed-Line Modes

Abstract: This communication proposes a new patch antenna with dual circularly polarized capability at 2.575 GHz. The design exploits the even and odd modes in a coplanar waveguide transmission line and enables simultaneous right- and left-handed circular polarization, with two individual excitation ports. A patch antenna is fed by multimode transmission line and the advantages and disadvantages are discussed. A prototyped antenna realized up to 20 dB isolation between ports with S21 <; -10 dB bandwidth of 87 MHz. Realized gains for the two modes of operation are 5.77 and 7.23 dBic. The proposed structure is compact and easy to manufacture.

G-Band Micro-Fabricated Frequency-Steered Arrays With 2 $^\circ$ /GHz Beam Steering

Abstract: In this paper, we describe micro-fabricated frequency-scanned slot waveguide arrays operating between 130 and 180 GHz for planetary landing radar The group delay dispersion of the feed line is increased by corrugating the bottom rectangular waveguide wall Both 16-element and 32-element linear arrays are fed by micro-coaxial corporate feed networks to narrow the beam in the non-scanning direction Two-dimensional (2-D) antenna arrays and feed networks are photo-lithographically fabricated using a sequential metal deposition process The 16-by-21 array demonstrates a 6° beamwidth and 2° /GHz steering over a 40° scan angle

Power recovery circuit based on partial standing waves

Abstract: A power recovery system includes a transmission line that is coupled to transfer an RF signal received via an antenna. The RF signal generates a partial standing wave in the transmission line and the transmission line has at least one standing wave anti-node. A power recovery circuit converts an anti-node signal from the at least one standing wave anti-node to a power signal.

Method to make RF switches and circuits with phase-change materials

Abstract: A radio frequency switch includes a first transmission line, a second transmission line, a first electrode electrically coupled to the first transmission line, a second electrode electrically coupled to the second transmission line, and a phase change material, the first transmission line coupled to a first area of the phase change material and the second transmission line coupled to a second area of the phase change material. When a direct current is sent from the first electrode to the second electrode through the phase change material, the phase change material changes state from a high resistance state to a low resistance state allowing transmission from the first transmission line to the second transmission line. The radio frequency switch is integrated on a substrate.

Periodic Leaky-Wave Antenna on Planar Goubau Line at Millimeter-Wave Frequencies

Abstract: A periodic leaky-wave antenna on a planar Goubau line is presented. This transmission line is formed by a planar single-wire waveguide on a thin dielectric substrate. Leakage is produced by adding dipoles along the line on the bottom face of the substrate. A coplanar waveguide is used to feed the antenna, which acts as a smooth transition between the input coaxial cable and the planar Goubau line. The advantage of using this line lies on its losses, lower than those of typical microstrip lines due to the absence of a ground plane. As a result, a higher radiation efficiency than in microstrip-fed antennas can be obtained while keeping similar advantages, e.g., low profile or low production cost. A prototype of the antenna at 40 GHz has been fabricated. Measurements of this prototype are presented in this letter.

Coaxial waveguide for travelling wave MRI at ultrahigh fields.

Abstract: At high magnetic fields the performance of a volume-type body coil inside a human sized MR-scanner is influenced by the waveguide action of the scanner's bore. This can result in undesirable strong radio frequency fields ) outside the coil's target volume. A radio frequency (RF) transmit system, exploiting this waveguide action of the bore, is proposed in this work. A coaxial waveguide section is introduced between the antenna and the imaging region. It is shown that the coaxial waveguide has several advantages over the initially proposed travelling wave setup based on the cylindrical waveguide. First, a novel radio frequency matching principle (based on the transmission line impedance matching) is feasible with the coaxial waveguide achieving better radio frequency transmission characteristics, such as homogeneity and power efficiency of field. In case of body torso imaging, the coaxial waveguide prevents unwanted specific absorptive rate (SAR) deposition outside the target region and thus, effectively decreases local peak SAR values by factor of 5. A 3-fold gain in the prostate can be achieved with the coaxial waveguide in comparison with the initially proposed travelling wave setup. Magn Reson Med 70:875–884, 2013. © 2012 Wiley Periodicals, Inc.

Dual-/Triple-Band Asymmetric Dipole Antenna for WLAN Operation in Laptop Computer

Abstract: A compact (31 mm 7 mm 0.8 mm) uniplanar antenna designed for wireless local-area network (WLAN) operations in laptop applications is proposed. To achieve triple-band (2.4/5.2/5.8 GHz) WLAN operation, the structure of the proposed antenna is devised as an asymmetric dipole type, in which the 2.4/5.2 GHz operating bands are excited along the meandered feed line connected to a rectangular radiating element, and the excitation of the 5.8 GHz band comes from its asymmetric counterpart (with C-shaped parasitic strip). Interestingly, the proposed triple-band antenna can be reduced to a dual-band (2.4/5.2 GHz) one by simply tuning the length of the C-shaped parasitic strip. The simulated effects on the antenna performances by tuning the various vital parameters have been studied and experimentally verified.

Dual linear and circularly polarized patch radiator

Abstract: A patch radiator suitable for operation with circular or dual linear polarizations is described. The patch radiator includes a patch antenna element (12) and a pair of excitation circuits (20a, 20b). The excitation circuits include a feed line (22,24) and a tuning circuit (26,28) configured such that a single feed line enables independent operation of each polarization. This allows for the operation of the patch and therefore array as either linear, slant, elliptical, or circular polarization.

A Bidirectional Circularly Polarized Array of the Same Sense Based on CRLH Transmission Line

Abstract: A bidirectional circularly polarized array of the same sense is proposed. The implementation is a combination of end-flre array, crossed dipoles, and composite right/left-handed transmission line (CRLH-TL). The proposed array consists of four dipoles spaced at a distance equal to ‚0=4 (‚0 is the wavelength in free space at the center frequency). For the bidirectional circular polarization of the same sense, the four dipoles are fed in-phase in a series-fed structure. A feed line that exhibits 0 - phase shift every ‚0=4 is needed. To satisfy the demand for the space distance and phase distribution in a series-fed array, the CRLH unit cell composed of lumped capacitors and inductors is employed and inserted in the feed line. Theoretical analysis is performed based on the balanced parallel stripline and design equations are presented for the determination of the lumped element parameters. The design method can be used in the design of the arrays with more elements. From the experimental results, the array ofiers a 4.2dBic bidirectional circular polarization gain. The bandwidth between which the impedance matching is better than i10dB and the axial-ratio is better than 3dB is 300MHz from 2.39 to 2.69GHz.

Radio frequency (RF) couplers

Abstract: An RF coupler implementable as an integrated circuit includes a first transmission line having a first line portion and a second line portion. A first end of the first transmission line is coupled to an input port for receiving an RF input signal. A second end of the first transmission line is coupled to an output port for providing an RF output signal. The RF coupler further includes a second transmission line formed between the first line portion and the second line portion such that magnetic field produced due to the RF input signal in the first line portion and the second line portion envelops the second transmission line. A first end of the second transmission line is configured as a coupled port for providing a coupled RF signal, and a second end of the second transmission line is coupled to a termination element to form an isolation port.

Cycling reference multiplexing receiver system

Abstract: A position tracking system for tracking a physical location of a radio frequency (RF) transmitter comprises at least four RF receiver antennae at known locations. Each receiver antenna receives RF signals from the RF transmitter. One receiver antenna is used as a reference antenna. A receiver channel unit is in communication with the RF receiver antennae. The receiver channel unit comprises a reference receiver channel and a measurement receiver channel. A multiplexer is dynamically configurable to selectively connect the reference receiver channel to the reference receiver antenna and to connect, in succession, each other receiver antenna to the measurement receiver channel. A comparator measures phase differences between the RF signals received by the reference antenna and those received by each other receiver antennae. A data processor computes the physical location of the RF transmitter from the phase differences measured by the comparator and the known locations of the receiver antennae.

State of the art of nonlinear transmission lines for applications in high power microwaves

Abstract: Nonlinear transmission lines have been used with great success in pulse sharpening for obtaining output fast pulse rise times in nanosecond and picosecond ranges. Nowadays recent research on this field has shown a great prospect for RF generation using these devices in aerospace application such as in ultra-wide band radar for communications, remote sensing and surveillance due to less attenuation and electromagnetic interference. Also other important applications are envisioned in high power microwave sources for battlefield communication disruption and space vehicle systems as they can replace electronic tubes without the need of vacuum and heating. A nonlinear transmission line basically consists of a lumped LC line using a nonlinear element (variable inductance or capacitance) or a continuous transmission line using a nonlinear medium (ferroelectric or ferrimagnetic). In this paper the state of art for both configurations are discussed as well as their main characteristics and limitations.

Miniaturized patch antenna

Abstract: The present invention relates to a miniaturized patch antenna assembly in UHF frequency band. The invention is notably useful in RFID applications. The patch antenna assembly comprises: - a multilayered dielectric substrate including at least a top layer, a middle layer and a bottom layer, - an electrically conductive patch structure on the upper surface of the top layer, said patch structure having a centre point located at the centre of patch structure surface and a feeding point electrically coupled to a feed line, - a ground plane on the lower surface of the bottom layer. According to the invention, it further comprises a slot etched in the patch structure, said slot surrounding the centre point of the patch structure. This slot aims to concentrate the surface current at the centre of the patch structure, which allows reducing its size.

Tri-band bandpass filters using modified tri-section stepped impedance resonator with improved selectivity and wide upper stopband

Abstract: This study presents tri-band bandpass filters using two variant designs based on tri-section stepped impedance resonators (SIR) to achieve passband selectivity. The passbands are centred about 2.4, 3.5 and 5.5 GHz, respectively. The first design pertains to an asymmetric stepped impedance stub-loaded tri-section SIR and the second one consists of embedded SIR. Both the techniques contribute in improving the selectivity by inserting transmission zero between first passband and second passband. With a simple extension of one of the input/output coupling feed lines transmission zeros are inserted between second and third passband. The filter exhibits a wide stopband till 10 GHz because of, cascading with the feed line, a low-pass filter with upper cutoff at 6.4 GHz. The passband insertion loss is within 2 dB. The group delay excursion for both the developed filters for the three passband suggests linearity of phase. Fabricated prototypes for both the variants are realised with simulated and measured results in good agreement.

Bluetooth/uwb circular patch antenna with dual band notches

Abstract: In this paper, we propose a new planar antenna for Ultra Wide-Band (UWB) and Bluetooth applications with two band notches. The band notch are designed to reject the Worldwide Interoperability for Microwave Access (WiMAX) applications based on the IEEE 802.16 standards for the frequency band 3.3-3.8 GHz and the Wireless Local Area Network (WLAN) applications band that based on the IEEE 802.11 standard for the frequency band of 5.15-5.825 GHz. The antenna consists of a circular patch, co-planner waveguide (CPW) feed line with 50 Ω input impedance, T-strip connected to the top of the patch and complementary circular slot type split ring resonator (SRR) is etched at the bottom edge of the patch. The antenna covers the UWB frequency band (3.1-10.6) GHz beside extra band for Bluetooth frequency range (2.4-2.48) GHz. The characteristics of the designed structure are investigated using finite element method based electromagnetic solver, HFSS. Promising return loss data with good matching, good gain, high efficiency and omni-directional radiation pattern are obtained.

System including tunable choke for hydrocarbon resource heating and associated methods

Abstract: A system and method for heating a hydrocarbon resource in a subterranean formation having a wellbore extending therein, include the use of a radio frequency (RF) source, an RF antenna to be positioned within the wellbore and a transmission line coupling the RF source and the RF antenna. A tunable choke is positioned on the transmission line between the RF source and RF antenna, and a controller is coupled to the tunable choke. The controller may be configured to tune the tunable choke to reduce a common mode current from propagating on an outside of the transmission line toward the RF source.

Dual Frequency Triangular Slotted Microstrip Patch Antenna for Ku Band Applications

Abstract: A single feed, compact, new shaped, dual band microstrip patch antenna has presented in this paper. Here three equilateral triangular slots are introduced in the three edges of the patch and a small feed line has used another edge of the patch to obtain the dual band. The antenna has a condensed structure where patch dimension is about 8.5mm by 7.96mm by 1.905mm leading to good bandwidths covering 13.15 GHz to 13.72 GHz and 16.04 GHz to 16.58GHz. The return loss of -19.00dB is achieved at the first resonant frequency at 13.61 GHz and -28.69dB is at second resonance frequency at 16.33GHz. Stable average peak gain that is observed across the operating band in both lower and higher frequency is almost 3.53dB and 5.562dB respectively .The radiation patterns are nearly omnidirectional with moderate gain in both these operating bands. Good results have been established in dual frequencies at 13.62GHz as downlink and 16.33GHz as uplink. This low profile nature and simple configuration of the proposed antenna show the way to easy fabrication and make it adaptable for the application in wireless and satellite communication Streszczenie. W artykule przedstawiono dwupasmową prostokątną antene mikropaskową o jednym doprowadzeniu i nowym ksztalcie. W trzech rogach znajdują sie trzy szczeliny w ksztalcie trojkąta rownobocznego, a w czwartym doprowadzenie linii. Antena posiada pasmo 13,15-13,72GHz oraz 16,04-16,58GHz. Niski profil oraz prosta konfiguracja wskazują na latwą metode produkcji oraz mozliwośc zastosowania w aplikacjach bezprzewodowych i komunikacji satelitarnej. (Dwuczestotliwościowa antena mikropaskowa z trojkątnymi szczelinami w zastosowaniu do pasma Ku).

Antenna and wireless communication device

Abstract: A small antenna operating at a plurality of frequency bands includes a first conductor plane in which a first split ring resonator and a second split ring resonator that have different resonant frequencies are formed and a feed line including a first branch line, a second branch line and a branch portion. Each of the split ring resonators includes a conductor region along an opening edge of an opening formed in the first conductor plane and a split portion cutting through a portion of the conductor region. One end of the first branch line is connected to the first split ring resonator and the other end extends to the branch portion across the conductor region; one end of the second branch line is connected to the second split ring resonator and the other end extends to the branch portion across the conductor region.

Design and simulation of double ridged horn antenna operating for UWB applications

Abstract: In this paper, the design and simulation of a modified double-ridged antenna is presented (demonstrated). The radiation phenomenon is based on the wave impedance transition from transmission waveguide line to the impedance of free space through ridges. This paper describes the design of an ultrawideband Double Ridged Horn antenna with VSWR less than 2, operating at 5.3GHz to 6.3GHz, 11.02GHz to 11.8GHz, 16.5GHz to 18GHz, 22.8GHz to 23.7GHz and 28GHz to 29.14GHz frequency ranges which are proved to be more suitable as a feed element in reflectors of the RADAR systems and EMC applications. A new coaxial line to double-ridged waveguide transition and a new technique for tapering the flared section of the horn are introduced to improve the return loss and the impedance matching. The ridges are used to lower the cut-off frequency, hence increasing the antenna's bandwidth. An Antenna having coax feed transmission line for radio frequency signal, provides protection of the signal from external electromagnetic interference. To boost the return loss, an external part called “back cavity” is attached to the waveguide. Results of simulation and the performance of a double ridged pyramidal horn antenna in terms of low VSWR (less than 2), high gain, ultra-wide operation frequency bandwidth operating at 5.3GHz to 6.3GHz, 11.02GHz to 11.8GHz, 16.5GHz to 18GHz, 22.8GHz to 23.7GHz and 28GHz to 29.14GHz are provided. The tool used for designing purpose was Ansoft HFSS version 12.0.

A Wideband Transmission Line Model for a Slot Antenna

Abstract: The traditional transmission line model for a slot antenna is typically only useful for the prediction of the first resonant mode. Here, a wideband transmission line model for a slot antenna is presented that describes the antenna's input impedance more accurately than previously published work, particularly at frequencies above the first resonant mode. To do this, we develop three improvements to the model: a modal equation that better approximates the frequency-dependent voltage distribution in the slot; an expression that captures more fully the inductive nature of the shorted ends of the slot; and a conductance-per-unit-length to predict the structure's loss characteristics. The results of this new wideband transmission line model are compared to commercial full-wave simulations and measurements for validation.

Ultra wideband antenna with WLAN band-notch characteristic

Abstract: The presented paper exhibits a coplanar waveguide (CPW)-fed symmetrical staircase shaped, planar monopole Ultra Wideband (UWB) antenna having dimensions 4030×l.6mm3 with 5GHz WLAN notch band characteristic. The staircase pattern in the radiating patch and the U-shaped slot resonator in the feed line are used to achieve the UWB and notch the 5GHz WLAN band, respectively. The proposed antenna has impedance bandwidth ranging from 2.84GHz-13.9GHz to cover UWB. Interference caused by WLAN band from 5.15GHz-5.35GHz and 5.725GHz-5.825GHz is notched effectively. The proposed antenna has been printed on FR4 substrate with dielectric constant of 4.4 and thickness of 1.6mm. Moreover, the fabricated prototype antenna shows a good agreement between the simulated and measured results.

Modified bow-tie antenna with strong broadband field enhancement for RF photonic applications

Abstract: We present a novel design of a subwavelength modified bow-tie antenna that is capable of generating strong broadband field enhancement in its extended feed gap. This modified bow-tie antenna is comprised of a conventional bow-tie antenna with capacitive extended bars attached to the apex points of the bow-tie. The feed gap between the two capacitive bars is separated with a deep subwavelength width for the generation of enhanced local electrical field. Three-dimensional finite element method model is utilized to systematically explore the properties of this antenna design. Through adjusting the bow-tie geometry and the substrate properties, the antenna structure is optimized with a central resonant frequency at 100 GHz. Highly enhanced electrical field is created between the extended bar under radio frequency (RF) illumination. With the optimized design, numer ical simulations show that a uniform field enhancement of more than 200 through the entire feed gap with a bandw idth of 40 GHz can be achiev ed. The strongly enhanced RF field within the gap can be applied to directly modulate guided optical wave propagating in a waveguide embedded in the substrate underneath the feed gap. This work builds up a bridge between devices in the RF and optical frequency regimes that may find many potential applications in RF photonic devices and systems. Keywords: Modified bow-tie antenna, broadband strong field enhancement, RF photonic applications