Showing papers on "Active antenna published in 2005"

A 60-GHz multilayer parasitic microstrip array antenna on LTCC substrate for system-on-package

Abstract: This letter describes a compact and high-gain multilayer parasitic microstrip array antenna (MPMAA). The design and performance of the proposed array antenna are presented. The antenna employs three layers with a 2/spl times/2 parasitic array on each layer. The developed prototype MPMAA employs a multilayer low-temperature co-fired ceramic (LTCC) substrate that is well suited to the assembly of MMIC chips. The fabricated MPMAA achieves a 7.17 dBi absolute gain at 60 GHz including the loss derived from the feeding parts and RF probe to measure its antenna performance. The spacing of the top layer of the parasitic array constructed by 2/spl times/2 elements has a free-space wavelength of 0.36 and the chip size is 10 mm/sup 2/. The fabricated MPMAA achieves both compact and high directional gain and satisfies the requirements for a millimeter-wave system-on-package (SOP).

Millimeter-wave high-efficiency multilayer parasitic microstrip antenna array on teflon substrate

Abstract: This paper proposes a highly efficient multilayer parasitic microstrip antenna array that is constructed on a multilayer Teflon substrate for millimeter-wave system-on-package modules. The proposed antenna achieves a radiation efficiency of greater than 91% and an associated antenna gain of 11.1 dBi at 60 GHz. The antenna size is only 10 mm /spl times/ 10 mm. Additionally, this paper describes a 60-GHz-band prototype antenna employing a multilayer Teflon substrate that is well suited to achieving high gain and a wide bandwidth. The measured performance of the prototype antenna is also presented.

Multi-mode input impedance matching for smart antennas and associated methods

Abstract: Smart antenna (22) includes a ground plane (41) , an active antenna element (30) adjacent the ground plane and having a radio frequency (RF) input associated therewith, and passive antenna elements (32) adjacent the ground plane. Impedance elements (60) are connected to the ground plane and are selectively connectable to the passive antenna elements for antenna beam steering. Tuning elements (34) are adjacent the passive antenna elements for tuning thereof so that an input impedance of the RF input of the active antenna element remains relatively constant during the antenna beam steering.

A novel fully integrated transmitter front-end with high power-added efficiency

Abstract: A novel fully integrated transmitter front-end with a simple structure is proposed to obtain both high power-added efficiency (PAE) and a compact RF-front structure. To have all these characteristics, a novel antenna operating as a radiator, a harmonic tuning circuit, and an output matching network of the power amplifier is proposed. Therefore, the direct integration of the output of the power amplifier and antenna can be achieved without any impedance transformers. From the measured results and fabrication, it is shown that the proposed transmitter front-end provides high PAE of 67.5% and compact and integrated RF-front structure by the size reduction of 43% compared with the conventional class-F active antenna for high PAE.

Compact smart antenna for wireless applications and associated methods

Abstract: A smart antenna (20) includes an active antenna element (30), a passive antenna element (32) laterally adjacent the active antenna element, and an impedance element (40) selectively connectable to the passive antenna element for antenna beam steering. A ground plane (40) includes a center portion (52) adjacent the active antenna element, and first and second arms (54, 56) extending outwardly from the center portion. The first arm is connected to the impedance element, and the second arm is laterally adjacent the first arm.

Reader/writer device and information recognition system

Abstract: PROBLEM TO BE SOLVED: To provide a reader/writer device and an information recognition system by which an active antenna can efficiently communicate with an object RFID tag. SOLUTION: The reader/writer device concerning this invention is the reader/writer device 11 in which a plurality of antennas 12 for reading and writing storage information by operating the RFID tag 13 are arranged, the plurality of antennas 12 are provided with an antenna 12 which communicates with the RFID tag 13 to be a communication object and other antennas 12 approximated to the antenna 12 and the approximated antennas 12 become states that it can not communicate with the target RFID 13 when the antenna 12 becomes the communication state with the object RFID tag 13. COPYRIGHT: (C)2006,JPO&NCIPI

A varactor-tuned active-integrated antenna using slot antenna

Abstract: A varactor-tuned active antenna which consists of a series feedback voltage-controlled oscillator (VCO) and a well matched slot antenna is proposed. The fabricated antenna shows stable oscillation at 5.8 GHz band, and the frequency varied from 5.73 to 5.97 GHz, with less than 1.28 dB of amplitude deviation over the frequency range. Since the fabricated active antenna is a simple structure where the operating frequency can be easily tuned through the varactor diode, it may be used as an element in phase-shifterless beam scanning systems. In addition, a capacitor for dc blocking is not necessary due to isolation between the active and radiating element.

Low profile smart antenna for wireless applications and associated methods

Abstract: A low profile smart antenna includes an active antenna element carried by a dielectric substrate, and active antenna element has a T-shape. Passive antenna elements are carried by the dielectric substrate, and they have an inverted L-shaped portion laterally adjacent the active antenna element. Impedance elements are selectively connectable to the passive antenna elements for antenna beam steering.

Broadband smart antenna and associated methods

Abstract: A smart antenna includes a ground plane, an active antenna element adjacent the ground plane, and passive antenna elements adjacent the ground plane. The passive antenna elements have different sizes for defining different resonant frequencies for increasing a bandwidth of the smart antenna. Dielectric layers having different dielectric constants may also be used for coating the passive antenna elements for defining different resonant frequencies. Impedance elements are connected to the ground plane and are selectively connectable to the passive antenna elements for antenna beam steering.

Cooling System for a Ka Band Transmit Antenna Array

Abstract: Active antenna arrays working at higher frequencies result in higher packaging densities. The antenna array under consideration operates at about 30 GHz and will be installed in an aircraft. Commercially available power amplifiers at these frequencies have an efficiency of typically 20 %, which results in high amounts of dissipated heat for the required high radiated power. The dissipated power, up to 9.5 kW as a worst case for a 50 × 50 element array, has to be transfered from the antenna to a heat exchanger or to the ambient air. Several cooling techniques including forced air and liquid cooling as well as heat pipes will be presented in this work, always considering the packaging density and the little space available. Simulations based on the software Flotherm led to the result that a liquid cooled cold plate is the most feasible approach while meeting all requirements. Experiments on a simplified model and comparison with simulations confirmed the results. Additionally, a forced air convection fin heat sink based on standard components was proposed, which can be used for an antenna demonstration model with 4 × 4 elements.

Ka-band Fresnel lens antenna fed with an active linear microstrip patch array

Abstract: The design of a linear microstrip array and Fresnel lens combination as a potential candidate for Ka-band satellite communications is presented. Medium-power amplifiers are distributed within the array to achieve a high EIRP required for satellite communications. This architecture may be used as an alternative to the conventional horn-fed reflector antenna with a single high-power amplifier.

S-band active phased array antenna with analog phase shifters using double-balanced mixers for mobile SATCOM vehicles

Abstract: We propose an S-band active phased array antenna (APAA) with analog phase shifters (PSs) that use double-balanced mixers (DBMs). The quadrature phase shift keying modulator integrated circuits (ICs) used as the phase shifters can control both the amplitude and phase of the input signal continuously and independently by using the control voltages. The phase and amplitude errors during phase rotation were 0.5/spl deg/ rms (max=1.7/spl deg/) and 0.3 dB rms (max=0.7 dB), respectively. The range in which the amplitude could be linearly changed was 7 dB. The proposed antenna exhibited sufficient performance for mobile vehicles to handle satellite communications: beam-pointing resolution of 0.04/spl deg/, beam-pointing accuracy in the null pointing of 0.4/spl deg/ rms, and sidelobe suppression with an amplitude taper achieved by setting the amplitude of the PS using two DBMs. Comparison between the analog PS and a reflection-type four-bit digital PS showed that although the analog one is unsuitable for use in a passive PAA, it is suitable for use in an APAA.

An x-band system-in-package active antenna module

Abstract: System-in-package (SiP) is based on the concept of combining all the electronic requirements of a system into a single package. Along with providing cost and size benefits, SiP with an integrated antenna can help mitigate the feed network losses and phase errors in an antenna array based application. This paper presents the development of a low cost, compact RF front end SiP solution for X-band. A printed antenna is integrated with a multilayer BGA package using low cost laminate substrates. This active antenna module can be further integrated into arrays and used for wireless as well as sensing applications.

An intermodulation suppression technique for transmit active phased array satellite antennas with multiple shaped beams

Abstract: A technique to improve the efficiency of multibeam transmit active phased array satellite antennas with shaped beams is proposed. The approach is based on selecting fundamentally different or orthogonal aperture phase distributions per beam, resulting in intermodulation beams that are different from the carrier beams for the same coverage. This allows for optimization for maximum effective isotropic radiated power and minimum intermodulation power over the coverage area with respect to the aperture phase excitation. Lower radiated intermodulation power means that the amplifiers can be operated more nonlinearly, resulting in higher antenna efficiency. Simulations for an extended Continental U.S. region suggest that the antenna dc power can be reduced by about 50% for four single carrier beams. The technique applies to any beam coverage regions, either identical or different.

Minimax robust M-beamforming for radar array with antenna switching

Abstract: We address the problem of estimating the movement parameters in non-Gaussian noise environments using an active radar array with antenna switching. The switch radar system is composed of a single transmitter, M receiving antennas, and a single receiving channel. We propose a new three-dimensional (3-D) power function which is exploited for beamforming and estimation of parameters of moving targets. Maximum peaks of this power function are used for estimation of the angle, velocity, and range of multiple moving targets. The robustness of the beamforming and the estimates is enabled by using Huber's M-estimates of the echoed transmitted radar signal. Two robust beamformers are studied: robust Huber and robust approximate median. Simulation demonstrates that the proposed robust beamformers provide a decreased sensitivity of the estimates with respect to noise components having heavy-tailed distributions.

An active antenna demonstrator for future AESA-systems

Abstract: As a part of the Generic AESA Demonstrator Program at Ericsson Microwave Systems we have worked with an active antenna demonstrator working at S-band. The antenna demonstrator, which consists of a phased array with 96 active elements, has been designed, manufactured and evaluated. An evaluation system has been put together at an antenna near-field range and we have used this demonstrator to get practical experience in all aspects from array aperture design, T/R-module production, antenna system design, assembly/integration and antenna system calibration and evaluation. The design was intentionally chosen to be "low-risk" and "high yield" to meet a tight project schedule and well-defined goals at antenna systems level. The goal was to demonstrate a stable active antenna function with an active receive array of approximately 100 elements and to evaluate a calibration scheme based on factory characterization. Both these goals have been fulfilled within a period of 2 years including initial design-and final evaluation phase.

Active integrated antenna techniques for beam control

Abstract: Active integrated antenna techniques have high potential for giving smaller size, lighter weight, lower cost and higher efficiency, in particular to millimeter-wave circuit-antenna systems. This paper gives a review of active integrated antenna techniques with emphasis on beam steering and retrodirective antenna arrays. Various beam steering operations of integrated antenna oscillator arrays using locking phenomena are presented. Beam steering arrays of such type have the feature that phase shifters are not necessary in the arrays. Arrays with higher harmonic output radiation can enlarge the beam steering range. Arrays of locked active antennas which operate as self-oscillating mixers can be beam controllable receiving antennas.

Design Considerations of an Active Integrated Antenna with Negative Resistance Transistor Oscillator

Abstract: The design of an active integrated antenna with negative resistance transistor oscillator has been described. Simple but reasonably accurate analysis of oscillation start-up and steady state operating frequency prediction is presented. The active antenna prototype was manufactured and its operating frequency, EIRP and radiation patterns were measured. Two of these antennas were integrated in active arrays coupled in Eand H-planes. The inter-element distance in the arrays was optimized to obtain inphase operation and mutual injection locking. Very good power combining efficiency was measured and beam scanning capabilities were demonstrated for both arrays.

Active frequency selective surfaces for antenna applications electronically to control phase distribution and reflective/transmissive amplification

Abstract: A planar dipole grid antenna is described deposited on an active frequency selective (FSS) or polarization sensitive surface (PSS) electronically tuneable to control the spatial phase distribution and reflective/transmissive amplification. Such dipole grids can be used, for example, in reflector antenna systems composed of multiple reflective and/or transmissive subsystems to achieve and serve highly cost-effective multi-purpose applications. It is discussed how the resonant frequency or/and the type of polarization can be tuned just by varying the steering voltage or current of electronically tunable components such as varactor diodes or YIG films, respectively, implemented and integrated with each of the radiating dipole elements. The theoretical analysis for this paper is based upon a specific Floquet theory approach for single/double/triple periodic antenna structures. The resulting system of coupled vector integral equations for the unknown electric and magnetic current distribution is numerically solved by applying the method of moments supported by Galerkin's process of weighting. The experimental investigations were performed by developing a waveguide simulation technique in the frequency range of 7 to 16 GHz. Results of selected measurements are presented for quantities such as: the spatially dependent reflection/transmission coefficients (magnitude, phase) as a function of signal frequency; the intrinsic input impedance/matching of the various dipole elements involved, etc.; and - in addition to that - the resulting electronically achievable phase advance/delay and amplification of the active antenna system as well. A one/two-dimensional enlarged planar dipole grid of about 40 mm /spl times/ 25 mm in aperture size was deposited inside an adequately tapered waveguide to reduce tolerance problems and to suppress higher order modes. Typical results are presented and discussed to demonstrate, e.g., that the resonant frequency/spl sim/-10 GHz can electronically be tuned around 9.85 GHz by a bandwidth of 7 % and around 10.1 GHz by 14 % in case of capacitive or inductive tuning, respectively. Investigations show that electronic tunability is achieved preferably by using high-Ohmic voltage controlled components instead of low-Ohmic current controlled components, for instance, supporting low-loss and low-noise performance. Using properly selected HEMT-type integrated transistors the achievable amplification measured turned out be about 5.4 dB at 10.3 GHz for an active one-element strip dipole grid (reflection-type amplifier) and about 3 dB at 9.3 GHz for an active one-element slot dipole grid (transmission-type amplifier), respectively. A concluding discussion indicates how such kind of planar/conformal dipole grids may set up an integrated system of multiple reflective/transmissive subreflectors of a powerful low-weight multi-purpose microwave antenna system of frequency multiplex and dual polarization capability to serve various technical applications at the same time and at a high degree of flexibility and cost-effectiveness as well.

Directional antenna system with multi-use elements

Abstract: Systems and methods for a wireless communication device having a switched multi-beam antenna and methods for manufacturing the same are described. One system and method includes a plurality of antenna of elements. Groups of the antenna elements cooperate to form active one or more antenna elements while other groups of the antenna elements cooperate to form a reflector for the active antenna elements. This creates a directed transmission or direction of positive gain for the antenna system. The same group of antenna elements can be switched so that other antenna elements cooperate to form the active element while another group forms a reflector for the active elements thereby providing a different direction of positive gain. The system can be used for various wireless communication protocols and at various frequency ranges.

Directive, broadband, high gain, active antenna system

Abstract: A broadband, high-gain, active antenna system is disclosed, which operates with a bi-directive reception pattern while in its standard configuration and with a directive reception pattern over several octaves of Radio Frequency (RF) spectrum when affixed with a tuned scatter-plate. As a standalone active antenna system the disclosed antenna probe element and the amplifier subassembly exhibit the bi-directional directive properties of a standard fixed length dipole, while the addition of a scatter-plate makes the antenna directive with separate frequency-dependant directive modes. The scatter-plate can be tuned such that these separate directive modes occur at convenient areas of the RF frequency spectrum. Other means of achieving directivity are disclosed using the antenna probe element and the amplifier subassembly.

A signal- and noise-measurement procedure for an antenna/RF receiver combination in a short-range automotive communication system

Abstract: A signal- and noise-measurement test procedure for an RF remote keyless entry (RKE) is presented. RKE systems are often designed for automotive applications, and include an RF receiver along with either an integrated antenna or a separately located external active antenna. Unlike previous methods, the new test procedure presented here allows measurement of the signal and noise levels at the output of an RKE system's RF receiver while the receiver is installed in its usual location on board the vehicle and connected with its antenna. This procedure also solves the problem of obtaining signal and noise measurements in systems with integrated receiver/antenna units. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 116–119, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21097

Beam Control in Unilaterally Coupled Active Antennas with Self-Oscillating Harmonic Mixers

Abstract: Beam control using active antenna arrays with self-oscillating harmonic mixers has been investigated. The active antenna is composed of a patch antenna receiving RF signal and a parallel feedback type oscillator which operates as the self-oscillating harmonic mixer, and down-converts the received RF signal into IF signal. The mixer has two ports for local oscillating (LO) signal. One is an output port extracting the LO signal. The other is an input port for an injection signal to synchronize the local oscillation. The mixers can be coupled unilaterally without other nonreciprocal components by connecting the output port to the input port in the next mixer. In the unilaterally coupled array, the phase differences of the LO signals between the adjacent mixers can be varied without phase shifters in injection locking state by changing the local free-running frequencies of the self-oscillating mixers. The receiving pattern can be controlled by combining the IF signals from the individual active antennas, which have phases associated with the LO signals. The IF is difference between the RF and double of the LO frequency so that arbitrary phase differences from 0 to 2π radian can be provided to the output IF signals. The experiments using the two- and three-element arrays demonstrated beam control capability.

CPW-fed patch antenna with switchable polarization sense

Abstract: This paper presents the design and development of a CPW-fed microstrip patch antenna with polarization reconfigurability (RHCP/LHCP). The basic antenna is a circular microstrip antenna excited by a CPW-fed diagonal slot and a CPW open end. First, experimental and simulated results are presented for the passive antenna. Then, an active antenna using beam-lead PIN diodes to switch the polarization sense is proposed. Simulations are presented including electrical parameters for the diode modeling. The deviation between simulated and experimental results is finally discussed.

Pattern reconfigurable millimeter wave microstrip quasi-Yagi active antenna

Abstract: A pattern reconfigurable microstrip quasi-Yagi active antenna is design by the finite-difference time-domain (FDTD) method in this paper This antenna operates at 50GHz and its radiation patterns can be reconfigured by using four switchable states The antenna can be applied to half-duplex communication and millimeter wave identification systems

Rotary joint device and active antenna

Abstract: PROBLEM TO BE SOLVED: To provide a rotary joint device in which a rotator can be auto-aligned to a rotary shaft by providing the structure of the rotator suitable for a load in an axial direction. SOLUTION: In a rotary joint device for an active antenna 1, the linking of a fixed part 10 and a rotary part 20 is formed from a thrust bearing 40 coupled to have a rotary shaft matched with that of the rotary part 20. COPYRIGHT: (C)2006,JPO&NCIPI

Active antenna radar system

Abstract: A radar system comprising a transmit antenna, a receive antenna and a mixer for combining a signal received by said receive antenna with a reference signal to produce an output signal. The transmit antenna includes an active antenna oscillator, the reference signal being derived from the active antenna oscillator. The active antenna oscillator is turned on and off by a pulse modulated biasing signal to produce a pulse modulated RF signal. The reference signal is delayed before being supplied to the mixer, the output of the mixer being used to determine when a detected object is a pre-determined distance from the system.

Amplifier-based active antenna oscillator design at 0.9-1.8 GHz

Abstract: The design of a stable narrowband active antenna oscillator at 0.9-1.8 GHz is reported. Novel use of a MMIC RF amplifier as the active device with two coupled patch resonators is presented. The design is based on EM-simulated antenna scattering parameters and manufacturer device measurements; this technique is confirmed by measurement of physical prototypes. Frequency tuning by varying the geometry or the supply voltage is observed and quantified.

Low profile smart antenna for wireless applications and associated methods

Abstract: A low profile smart antenna includes an active antenna element carried by a dielectric substrate, and active antenna element has a T-shape Passive antenna elements are carried by the dielectric substrate, and they have an inverted L-shaped portion laterally adjacent the active antenna element Impedance elements are selectively connectable to the passive antenna elements for antenna beam steering