Showing papers on "Active antenna published in 2016"

Tunable duplexing circuit

Abstract: A tunable duplexer circuit is described, wherein the frequency response as well as bandwidth and transmission loss characteristics can be dynamically altered, providing improved performance for transceiver front-end applications. The rate of roll-off of the frequency response can be adjusted to improve performance when used in duplexer applications. A method is described where the duplexer circuit characteristics are optimized in conjunction with a specific antenna frequency response to provide additional out-of-band rejection in a communication system. Dynamic optimization of both the duplexer circuit and an active antenna system is described to provide improved out-of-band rejection when implemented in RF front-end circuits of communication systems. Other features and embodiments are described in the following detailed descriptions.

Spectral, Energy, and Economic Efficiency of 5G Multicell Massive MIMO Systems with Generalized Spatial Modulation

Abstract: This paper studies generalized spatial modulation (Gen-SM) schemes in multicell multiuser massive multiple-input multiple-output (MIMO) systems as a promising high-throughput and energy-efficient technique for fifth-generation (5G) wireless networks. A detection algorithm for such systems is proposed based on linear processing techniques. By applying the concept of order statistics, a general framework for approximating the achievable sum rates with linear detection is also given. The probability of detecting antenna combinations is analyzed and is used to approximate the sum-rate performance with practical channel conditions, such as antenna correlation, imperfect channel information, and pilot contamination. The fundamental trade-off between spectral efficiency (SE) and energy efficiency (EE) is also investigated. Despite offering less SE, spatial modulation (SM) with a single active antenna per user is shown to be the most energy-efficient transmission mode among the Gen-SM class. Within the operating range of SM (i.e., in the low-to-moderate SE regime), SM is demonstrated to achieve better EE compared with conventional massive MIMO schemes. The performance in terms of economic efficiency, indicating economic profitability (in monetary unit per second), is also analyzed and is shown to serve as a complementary performance metric, enabling an implicit trade-off between SE and EE.

Wireless communications package with integrated antenna array

Abstract: Antenna package structures are provided to implement wireless communications packages. For example, an antenna package includes multilayer package substrate, a planar antenna array, antenna feed lines, and resistive transmission lines. The planar antenna array includes an array of active antenna elements and dummy antenna elements surrounding the array of active antenna elements. Each active antenna element is coupled to a corresponding one of the antenna feed lines, and each dummy antenna element is coupled to a corresponding one of the resistive transmission lines. Each resistive transmission line extends through the multilayer package substrate and is terminated in a same metallization layer of the multilayer package substrate.

Three dual polarized 2.4GHz microstrip patch antennas for active antenna and in-band full duplex applications

Abstract: This paper presents the design, implementation and interport isolation performance evaluation of three dual port, dual polarized 2.4GHz microstrip patch antennas. Input matching and interport isolation (both DC and RF) performance of implemented antennas has been compared by measuring the input return losses (Sii, S22) and interport isolation (S12) respectively at 2.4GHz. Two implemented single layer antennas provide around 40dB RF interport isolation while the multilayer antenna has 60dB isolation between transmit and receive ports at centre frequency with DC isolated ports. The multilayer antenna provides more than 55dB interport isolation for antenna's 10 dB input impedance bandwidth of 50MHz.

Recent advances in the radiated two-stage MIMO OTA test method and its value for antenna design optimization

Abstract: This paper discusses recent developments with the two-stage MIMO OTA test method. It first introduces the concept of the radiated two-stage (RTS) method which is based on a first stage of antenna pattern measurement followed by a second stage of throughput measurement using a signal generated by convolving the device antenna pattern with the desired spatial channel model. The resulting signal is applied to the DUT either through a conducted or radiated connection. The radiated version of the two-stage method was approved by 3GPP in Technical Report 37.977 v12.0.0 [1]. The primary advantage of the RTS method is that arbitrary 2D or 3D spatial channel models can be emulated using a low-complexity SISO anechoic chamber. The potential extension of the RTS method to active antenna systems was covered in [2] and the development of the antenna test function (ATF) defined in [3] was covered in [4]. Measurement uncertainty analysis for RTS is provided in this paper including the impact from degraded isolation level and antenna pattern error. This paper examines recent measurement results and the insight that can be gained for device designers by examining the antenna patterns measured with the aid of the ATF and also the many signal metrics that can then be calculated in order to predict and explain device performance. Such insights into the underlying reason for device performance are valuable to device and antenna designers and are only possible when using the RTS MIMO OTA test method.

Fabrication and measurement of a large, monolithic, PCB-based AESA

Abstract: This paper discusses a fabrication approach and experimental validation of a very large, planar active electronically scanned array (AESA). The planar AESA architecture employs a monolithic printed circuit board (PCB) with 768 active antenna elements at X-Band. Manufacturing physically large arrays with high element counts is discussed in relation to construction, assembly and yield considerations. Measured active array patterns of the ESA are also presented.

Asymmetric coupled Polarization Switchable Oscillating Active Integrated Antenna

Abstract: Polarization Switchable Oscillating Active Integrated Antenna (AIA) is proposed in this paper Active antenna consisting of an amplifier integrated with a two-port radiator, can be switched between three polarization states by controlling the bias voltage of switches (PIN diode) Asymmetric coupled T-shaped two-port microstrip patch radiator is designed to radiate more power than transmit back in the feedback path Field-effect transistor (FET) in the circuit is efficiently used due to low coupling power and provides high gain Proposed antenna is printed onto a single-layer of substrate with relative dielectric constant of 22 and thickness of 0762 mm Printed antenna shows stable oscillations in all three states; left hand circular polarization (LHCP), linear polarization (LP) and right hand circular polarization (RHCP) Measured results are well matched with the simulated results The received power in case of asymmetrical coupled AIA is around 45 dB higher than that of symmetric case at same impedance matching Proposed antenna is suitable for satellite, wireless communication applications and can be used as an element for spatial power combining planar arrays

Active Antenna Tracking System with Directional Antennas for Enhancing Wireless Communication Capabilities of a Networked Robotic System

Abstract: This paper presents a networked robotic system design capable of enhancing wireless communication capabilities communication range and bandwidth. The core of the system is active antenna tracking with directional antennas. The proposed system is decentralized and consists mainly of a mobile robot system and a command center system. Each system is equipped with off-the-shelf network devices such as antennas, access points AP, and network switches. For directional antennas to be beneficial to our system, we propose a weighted centroid algorithm WCA to provide active antenna tracking and direction-of-arrival DOA estimation. This system can be used in GPS-denied environments as our system does not require the aid of additional sensors to provide location information. Through extensive field experiments in different environments, including a fire training center and with various antenna selections, such as omni-to-omni, omni-to-directional, and directional-to-directional antennas, we demonstrate the effectiveness of our proposed system. We expect that our system can be applied in a variety of rescue, surveillance, and emergency scenarios where high bandwidth and long-distance communications are needed.

Generalized spatial modulation with transmit antenna grouping for correlated channels

Abstract: In this paper, an effective generalized spatial modulation (GenSM) scheme with transmit antenna grouping is proposed to overcome the performance degradation caused by correlated channels. In the proposed scheme, the transmit antennas are divided into several equal-sized groups, and spatial modulation (SM) is carried out to select one active antenna in each group independently. It is quite different from the conventional GenSM which jointly selects active antenna set. Apart from the straightforward block grouping method, which collects the adjacent antennas to the same group, interleaved grouping is also introduced. It can maximize the average distance between the antennas in the same group, since the channel correlation depends on it. To evaluate the performance, a closed-form expression of the average bit error probability (ABEP) upper bound is derived for all proposed grouping methods and Monte-Carlo simulations are conducted to verify the analysis and reveal the performance gain of the proposed scheme in terms of bit error rate (BER) in comparison with conventional GenSM and SM.

Load Balancing With 3-D Beamforming in Macro-Assisted Small Cell Architecture

Abstract: Small cell is an attractive and promising technology for improving capacity in traffic hotspots using cell densification. We consider the traffic load-balancing problem for a macro-assisted small cell architecture exploiting the flexible 3-D beamforming facilitated by the adoption of the active antenna system at base stations. Specifically, 3-D user equipment (UE)-specific beamforming is utilized for traffic load balancing due to its unique feature that the received signal is maximized, while the interference is limited with narrower beamwidth. We propose a novel traffic load-balancing algorithm based on cell association and cell sectorization using 3-D UE-specific beamforming, and the performance of the proposed algorithm is evaluated via system-level simulations. Results show that cell edge user throughput and cell average throughput both improve significantly with the proposed load-balancing algorithm compared with the conventional sectorization with fixed antenna down-tilt scheme. In addition, in denser small cell scenarios, our proposed scheme can further increase the load-balancing gain with reduced cell planning efforts compared with the conventional scheme.

Digital beamforming antenna array with polarisation multiplexing for mobile high-speed satellite terminals at Ka-band

Abstract: In this contribution, a planar antenna array terminal for mobile satellite communications at Ka-band is proposed. This Earth station on mobile platform uses separate transmit and receive apertures to obtain a flat design well suited for aeronautical applications. Digital beamforming is applied for fast beam scanning, tracking, and enhanced post-processing capabilities. The active antenna elements exhibit dual polarisation to comply with a four-colour spot beam arrangement commonly used by high-throughput satellites. Advanced frontend packaging concepts for a high integration density enable half wavelength element spacing. This prevents grating lobes and yields a large scanning range. A modular approach allows to flexibly adapt the array size to the application specific needs. An 8 × 8 receiver (Rx) array at 20 GHz and a 16 × 3 transmitter array at 30 GHz are demonstrated. The measured results obtained in conjunction with inter-element decoupling validate the approach. The principal suitability of the Rx array for the intended application is tested in a field experiment.

Space-Time Index Modulation

Abstract: In this paper, we present a new multi-antenna modulation scheme, termed as {\em space-time index modulation (STIM)}. In STIM, information bits are conveyed through antenna indexing in the spatial domain, slot indexing in the time domain, and $M$-ary modulation symbols. A time slot in a given frame can be used or unused, and the choice of the slots used for transmission conveys slot index bits. In addition, antenna index bits are conveyed in every used time slot by activating one among the available antennas. $M$-ary symbols are sent on the active antenna in a used time slot. We study STIM in a cyclic-prefixed single-carrier (CPSC) system in frequency-selective fading channels. It is shown that, for the same spectral efficiency, STIM can achieve better performance compared to conventional orthogonal frequency division multiplexing (OFDM). Low-complexity iterative algorithms for the detection of large-dimensional STIM signals are also presented.

Spatial Correlation Characterization of a Full Dimension Massive MIMO System

Abstract: Elevation beamforming and Full Dimension MIMO (FD-MIMO) are currently active areas of research and standardization in 3GPP LTE-Advanced. FD-MIMO utilizes an active antenna array system (AAS), that provides the ability of adaptive electronic beam control over the elevation dimension, resulting in a better system performance as compared to the conventional 2D MIMO systems. FD-MIMO is more advantageous when amalgamated with massive MIMO systems, in that it exploits the additional degrees of freedom offered by a large number of antennas in the elevation. To facilitate the evaluation of these systems, a large effort in 3D channel modeling is needed. This paper aims at providing a summary of the recent 3GPP activity around 3D channel modeling. The 3GPP proposed approach to model antenna radiation pattern is compared with the ITU approach. A closed-form expression is then worked out for the spatial correlation function (SCF) for channels constituted by individual antenna elements in the array by exploiting results on spherical harmonics and Legendre polynomials. The proposed expression can be used to obtain correlation coefficients for any arbitrary 3D propagation environment. Simulation results corroborate and study the derived spatial correlation expression. The results are directly applicable to the analysis of future 5G 3D massive MIMO systems.

A Novel SM-Based MIMO System With Index Modulation

Abstract: Multiple-input multiple-output systems with spatial modulation (MIMO-SM) have been recently proposed for high data rate, low complexity transmission schemes. However, in the SM, the antenna of the transmitter is randomly activated by the spatially modulated information bit sequence. Due to bad conditions of the active antenna's channel determined by the SM technique, the system would be likely to transmit frame with errors. This causes a significant reduction in the system performance. In this letter, to eliminate the bad effects of the channel assignment of the SM, we propose a novel SM-based MIMO system with index modulation technique (SM-MIMO-IM) when operating over i.n.d. and i.i.d. Rayleigh fading channels. The average symbol error rate (SER) and bit error rate (BER) of the proposed scheme are derived. It can be seen from numerical results that SM-MIMO-IM provides significant performance improvements and additional diversity gain compared to the classical SM and other some techniques given in the literature. Furthermore, the proposed mathematical analyses have been verified through the Monte-Carlo simulations.

Method for optimizing the orientation of a remote-control device with respect to a rolling drone

Abstract: The remote-control device ( 16 ) comprises an antenna for the radio link with the drone, and a touch screen ( 20 ) displaying an image captured by the camera of the drone. The method comprises the steps of: a) determination of the active antenna ( 28 b ); b) determination of the device model used; c) search, in a table of an applicative piloting software, for information of relative orientation with respect to the active antenna with respect to the device body; d) display of the image on the touch screen so that the top of a scene captured by the camera of the drone appears (A) to the user at the bottom of the screen ( 20 ) if the orientation of the antenna with respect to the device body does not correspond to the direction (D) of the drone, and appears (B) to the user at the top of the screen ( 20 ) if the orientation of the antenna with respect to the device body corresponds to the direction (D) of the drone, so as to produce an anti-natural display (A) leading the user to return the device (A′), hence placing the antenna in the direction (D) of the drone.

Design of a compact multilayer circularly polarized phased array transmit antenna system for satellite applications

Abstract: An active phased array antenna which can scan its beam direction to a wide range of scan angles is presented in this paper. The paper proposes a new technique to compact a phased array antenna and making it suitable for applying in satellite payloads. This antenna should transmit high data rate signal from satellite to ground stations; and by spatial power combining the needed Effective Isotropic Radiated Power (EIRP) for the transmission link will be provided. The main beam can be scanned to 50° from normal. Polarization of the radiated wave of this antenna is circular. The designed antenna benefits from microstrip technology and has a unique low mass multilayer structure with two different substrates. For implementing antenna’s RF circuits, Microwave Monolithic Integrated Circuits (MMICs) have been used and they are integrated expertly with microstrip radiators. Beam controller board sends necessary commands to MMICs for setting phase and amplitude of each array module. For decreasing side lobe level in high scan angles, genetic algorithm is applied and excitations of array elements are optimized. Design stages and simulation results of the array antenna are summarized in this paper and the results are compared with test results.

Joint Design of the Spatial and of the Classic Symbol Alphabet Improves Single-RF Spatial Modulation

Abstract: A new joint spatial and classic symbol alphabet is designed for spatial modulation (SM)-based multiple-input multiple-output systems. The employment of multiple active antennas instead of a single active antenna is proposed for increasing the achievable throughput and the joint design of the antenna selection and classic transmit symbol is explored, while maintaining the compelling advantages of SM. This framework combines the bit-to-antenna mapping and classic bit-to-constellation mapping into a single function, which defines the joint-alphabet and the joint optimization of the amplitude-phase modulation and its constellation for transmission over multiple active antennas. The conventional SM system is also interpreted within our framework. An example design is proposed, which aims for a high spectral efficiency of 11 b per channel use, achieving a gain of up to 5 dB over generalized SM (GSM).

Bi-directional active and passive meandered circularly polarized CRLH-inspired leaky-wave antennas based on substrate integrated waveguide

Abstract: Bi-directional active and passive meandered circularly polarized (CP) composite right/left-handed (CRLH) inspired substrate integrated waveguide (SIW) based leaky-wave antennas (LWAs) are presented. By meandering the microstrip line, the dimension of the proposed five-cell antenna along the scanning plane is reduced by 33.5% compared to the original CP CRLH LWA based on SIW [1]. Furthermore, incorporating the bi-directional amplifiers, the current distribution of the antenna is manipulated to control the radiation characteristics. The proposed active meandered CP CRLH LWA supports both transmitting and receiving operation while delivering enhanced spatial resolution.

Optimization of Spectrum Usage and Coexistence Analysis of DVB-T and LTE-800 systems

Abstract: This paper investigates the possible coexistence issues between the digital video broadcasting-terrestrial (DVB-T) system and the long term evolution (LTE) that operate in adjacent frequency bands. The proposed methodology for interference assessment evaluates the DVB-T performance degradation in presence of aggregate LTE-800 interference targeting the territory of Macedonia as evaluation area. The simulation analysis quantifies the percentage of interference degraded pixels and obtains the probability of pixel DVB-T service degradation. Furthermore, a measurement trial complements the simulation analysis through the evaluation of the influence of active antenna usage by the DVB-T receivers. The simulation and measurement results in this particular case confirm that the alignment of the active DVB-T receiving antenna towards the LTE-800 base station can substantially increase the degradation whereas aligning of the active DVB-T receiving antenna towards the DVB-T transmitter maintains the efficient TV reception. Finally, this paper proposes a simple algorithm for optimal LTE frequency arrangement, resulting in significant reduction of the LTE interference towards the DVB-T system.

Electrical properties analysis of conical radome

Abstract: For anti-radiation missile radome, to ensure the electrical properties of a passive antenna, it needs higher microwave transmittance in lager frequency range; for active antenna, on the basis of ensuring microwave transmittance, it also needs to restrict more indicators such as 3dB beam width variations and sighting errors in operating frequency of active antenna. Moreover, in order to facilitate design and simulation, the shape of aircraft radome usually use regular geometric structure such as conic, hemispherical and tangent ogive structure to approximately substitute in engineering. In this paper, for the needs of actual project, we simulate and analyze the conical radome with A-sandwich structure by four-port equivalent transmission line theories and PO physical optics. Then we can achieve electrical properties indicators of radome which include that microwave transmittance is larger than 80% in 2∼ 16GHz band and the variation of the half power beam width is smaller than 10% when the frequency is 13GHz and the sighting error is smaller than 0.2°.

Photonic Band Gap Aperture Coupled Fractal Shape Tri-Band Active Antenna

Abstract: A modified Koch fractal shape is used to decrease the dimensions of an antenna and resonates at more than one band for agricultural application. A new feeding technique of aperture coupled method called a non-uniform annular Photonic Band Gap is applied in order to integrate the designed antenna to the active elements. Subsequently, a transmission line transformer is designed using Genetic algorithm to achieve a perfect matching between the active element (amplifier) and the load (antenna). The proposed antenna is designed and fabricated. The results show that the proposed antenna has a high gain of 20.5 dB, 21 dB, and 22 dB at 0.915 GHz, 1.8 GHz and 2.45 GHz respectively with a compact size and low cost. The results predict its prospect as a promising alternative to the conventional one, which is compatibly applicable to agriculture applications especially when multiband function is required.

Vertical sectorization in self-organizing LTE-advanced networks

Abstract: Cellular radio networks continuously evolve to respond the exponential growth in data traffic volume in mobile communications Active antenna technology contributes to this evolution by introducing vertical sectorization, which splits the horizontal sector into two subsectors with respect to the elevation plane and doubles the number of cells that can be deployed However, in order to guarantee a reliable and near-optimal operation of vertical sectorization in a system that applies universal frequency reuse, such as LTE-advanced, co-channel interference mitigation is essentially needed In this article we propose a decentralized self-optimization method that can be used to mitigate the undesirable inter-cell interference by self-tuning the electrical antenna downtilt toward the optimal antenna elevation angle The performance evaluations for the proposed self-optimization method are carried out for both coordinated and uncoordinated subsector transmission scenarios within the LTE-advanced framework using a dynamic LTE-advanced compliant system level SON simulator Based on the extensive performance evaluations carried out for a realistic urban scenario, it is found that self-optimization improves the vertical sectorization performance 25 % in terms of virtual load Furthermore, the performance gain reaches up to 30 % when vertical vectorization is provided with dynamic point selection and muting feature Therefore, the article concludes that in LTE-advanced networks vertical sectorization can largely benefit from the antenna self-optimization and outperform the traditional horizontal sectorization approach with low algorithmic complexity

Antenna for active - passive seeker

Abstract: Disclosed is an antenna for an active-passive seeker which can respond to an active Ka-band and a passive broadband signal. The present invention comprises: a passive antenna part realized in the shape of a ring, having multiple spiral antennas arranged to receive signals in different frequency bands preset for the ring, and transmitting the signals, which have been received in different frequency bands, to a reception part; and an active antenna part realized in the shape of a circle, arranged at the center of the passive antenna part, radiating a transmission signal transmitted from a transmission part, and realized as a waveguide slot array antenna for receiving a reflected signal, which has been reflected on a target, as a received signal and transmitting the reflected signal to the reception part.

Base station apparatus and resource management method and data processing method in wireless communication system

Abstract: Disclosed herein are a base station apparatus, a resource management method, and a data processing method. The base station apparatus includes: a remote active antenna unit configured to perform transmission and reception of a wireless signal to and from a terminal; and a central unit connected to the remote active antenna unit, configured to process a signal received from the terminal or a signal to be transferred to the terminal, and configured to transfer resource allocation information to the remote active antenna unit, in which the remote active antenna unit schedules a data and a resource for the terminal based on resource allocation information received from the central unit.

The active RX-TX microstrip patch antenna

Abstract: The design and the operation of the active RX-TX microstrip patch antenna are considered. The antenna design is based on the use of one-port resonant transistor amplifier with the opened resonant system. Resonant system is realized on microstrip patch antenna. The antenna operation assumes the implementation of receiving and transmitting modes simultaneously. The switching between receiving and transmitting modes does not need to be implemented. The using of presented active antenna in transponder design of RFID systems and antenna arrays is discussed.

Beam switched antenna design for jamming mitigation of legacy GPS receivers

Abstract: We propose a low-cost solution for jamming mitigation of GPS by electronically switching antenna beam. Jamming signals are assumed to be directed from low elevation angles so that antenna rejection from zenith to low elevation must be improved by switching from wide angle half power beam width to a narrow one. Using low-cost, commercially available ceramic patches, four-element antenna array and its feed network are designed and one of the elements is designated as the normal (default) mode operation of the antenna. Proposed system can easily be replaced with existing active antenna to improve anti-jam capability of the receiver.

Fixed frequency broadside–endfire beam steerable antennas

Abstract: A novel reconfigurable broadside–endfire microstrip antenna is proposed. The beam steering is achieved by reconfiguring the ground plane. The ground plane can be reconfigured either into a high-impedance surface for broadside radiation or into a surface waveguide for endfire radiation. A DC bias line, not connected to the folded dipole feed in any way, is used to switch the PIN diodes. PIN diodes are soldered on the back of the antenna and have no possibility of interfering with the feed. The proposed antenna is designed to work at the ISM 2.45 GHz band with a combined 2:1 VSWR bandwidth of 110 MHz and a combined radiation coverage of 133° on the H-plane. A 5 V power supply or a 9 V battery can be used to operate the active antenna.

Active antenna architecture with reconfigurable hybrid beam formation

Abstract: The antenna architecture comprises a hybrid beamformer consists of a part, trainers Ny quasi-optical beams stacked, each forming quasi-optical beam having a waveguide parallel plate provided with a radiating aperture linear and including a lens (13) and internal cones provided with bundles of access ports, each forming quasi-optical beams being adapted to form beams in two bands of transmission and reception frequencies according to a first direction space, and secondly, at least one forming electronic beams comprising a combination device (34) connected to Nx phase control channels and amplitude, each phase control chain and amplitude being connected to a respective beam access port of each trainer quasi-optical beams, the forming of electronic beams being adapted to form beams in a second direction space orthogonal to the first direction.

Low-cost phase shifter and calibration solution for multi-channel receiver

Abstract: The design of a multi-channel receiver phase shifter based vector multiplier for high performance and low-cost active antenna array is presented in this paper. A receiving array architecture that combines analog beamforming is to offer a solution for the phase array and smart antenna application. In the architecture, a system with simple calibration procedure is presented to decrease the phase deviation with phase shift and gain control. Therefore, continuously adjustable 360° phase with resolution 0.18° control can be achieved.

Importance and measurement of phase-stiffness in RF switching amplifiers

Abstract: Phase-stiffness is a measure of the ability of an RF power amplifier to tolerate disturbance injected into its output. Phase-stiffness of conventional (linear) RF power amplifiers used in phased-array radar results from inserting circulators and isolators on their output as they can not tolerate typical disturbances arising from antenna mismatch and signals arriving from mutual coupling of array elements. We show that the output stage of a RF switching amplifier employing a single AlGaN/GaN HEMT loaded with an inductor exhibits high tolerance to external signal disturbance at the carrier frequency. This RF amplifier architecture shows promise for use in phase-array radar and active antenna array transmit/receive modules as this may operate without isolators.