Switched Beam Smart Antenna Research Articles

Integration of the modified Butler matrix and decoupling network for beam‐steering antenna array

In this article, the design and realization of a planar microstrip array antenna with a 4 × 4 modified Butler matrix is presented. The proposed switched-beam smart antenna operates at 4.95 GHz. The significant purpose of this research is mutual coupling reduction between antennas of the array. Therefore, the microstrip array antenna is arranged as E-plane mode and the novel decoupling network is used to reduce the mutual coupling. The mutual coupling of the proposed structure is measured −35 dB at 4.95 GHz frequency. The mutual coupling reduction of 17 dB is achieved by using the decoupling network. Also, the impedance bandwidth of the proposed structure with |S11| < −10 dB is about 300 MHz (6%) operating at the center frequency of 5.05 GHz and the average gain of 10.6 dB is obtained.

Smart antenna design alimented by a 4x4 butler matrix

In the last decades, the development of efficient antennas for wireless power transfer applications has gained great attention from researchers worldwide and has become a vital research topic. In this paper, we propose the optimum design and implementation in microstrip technology of a switched beam smart antenna alimented by a 4x4 butler matrix (BM) for a microwave wireless power transmission system (MPT) at 5.8 GHz. The proposed smart antenna consists of a four linear microstrip patch antenna array and a 4x4 butler matrix beamforming network. It was able to form and steer four orthogonal beams in the four directions (±39°, and ±15°). Furthermore, it exhibited a high gain of 17.98 dB and good simulated and measured return losses. The design, optimization and simulation of the smart antenna components were performed using advanced design system (ADS).

CL-SA-OFDM: Cross-layer and smart antenna based ofdm system performance enhancement

The growing usage of wireless services is lacking in providing high-speed data communication in recent times. Hence, many of the modulation techniques are evolved to attain these communication needs. The recent researches have widely considered OFDM technology as the prominent modulation mechanism to fulfill the futuristic needs of wireless communication. The OFDM can bring effective usage of resources, bandwidth, and system performance enhancement in collaboration with the smart antenna and resource allocation mechanism (adaptive). However, the usage of adaptive beamforming with the OFDM leads to complication in the design of medium access layer and which causes a problem in adaptive resource allocation mechanism (ARAM). Hence, the proposed manuscript intends to design an OFDM system by considering different switched beam smart antenna (SBSA) along with the cross-layer adaptive resource allocation (CLARA) and hybrid adaptive array (HAA). In this, various smart antenna mechanism are considered to analyze the quality of service (QoS) and complexity reduction in the OFDM system. In this paper, various SA schemes are used as per the quality of service (QoS) requirement of the different users. The performance analysis is conducted by considering data traffic reduction, bit-rate reduction, and average delay.

Design and Performance Analysis of Segmented Wireless Sensor Networks

This article presents the design and a theoretical performance analysis of a segmented wireless sensor network whose sink node is equipped with a switched-beam smart antenna. We compare the performance of the proposed segmented system against that of a conventional wireless sensor network (WSN) where all the nodes contend to access the medium in order to identify the system's conditions where the use of a smart antenna is justified. Our results show that the segmented network outperforms the WSN by reducing the cluster formation time in up to 25 with similar energy savings.

Self-reconfigurable implementation for a switched beam smart antenna

We present a self-reconfigurable embedded system for a switched beam smart antenna that can steer the beam pattern into a desired direction, handle arithmetic overflow, and respond to user-specified constraints on accuracy and resources. The main component (adaptive beamforming) is implemented as a fully customized hardware in fixed-point arithmetic. By varying the numerical formats and desired beam patterns, we generate a set of hardware configurations, which can then be selected at run-time via a dynamic manager implemented in software. The self-reconfigurable embedded system is implemented and tested on a Programmable System-on-Chip (PSoC). Results are presented in terms of resources, accuracy, and run-time hardware adaptation. This work illustrates the benefits of run-time reconfiguration technology on PSoCs for the implementation of switched-beam smart antennas.

AIS Algorithm for Smart Antenna Application in WLAN

Increasing numbers of wireless local area networks (WLAN) replacing wired networks have an impact on wireless network systems, causing issues such as interference. The smart antenna system is a method to overcome interference issues in WLANs. This paper proposes an artificial immune system (AIS) for a switch beam smart antenna system. A directional antenna is introduced to aim the beam at the desired user. The antenna consists of 8 directional antennas, each of which covers 45 degrees, thus creating an omni- directional configuration of which the beams cover 360 degrees. To control the beam switching, an inexpensive PIC 16F877 microchip was used. An AIS algorithm was implemented in the microcontroller, which uses the received radio signal strength of the mobile device as reference. This is compared for each of the eight beams, after which the AIS algorithm selects the strongest signal received by the system and the microcontroller will then lock to the desired beam. In the experiment a frequency of 2.4 GHz (ISM band) was used for transmitting and receiving. A test of the system was conducted in an outdoor environment. The results show that the switch beam smart antenna worked fine based on locating the mobile device.

Montecarlo Simulation Applied to Measurement of the Impact of the Smart Antenna Technology in Digital Cellular Systems

The smart antenna technology has received increasing interest due to its capability for improving the performance of wireless radio systems. In this work, we studied the throughput maximization in a digital cellular system when a smart antenna array is implemented. We focus, in the study of the downlink of a 3G cellular system and consider a packet data direct-sequence code division, multiple access (DS-CDMA). Our methodology is based on the Montecarlo simulation technique, and it is used to show that it is possible to obtain a signifi increment in the throughput of the system due to the switched beam smart antenna array. From our results we conclude that it is feasible to consider the application of this technology in 4G environments.

Implementation of Switched Beam Smart Antenna Using Artificial Neural Network

The capacity enhancement promised by switched beam smart antenna is a function of efficient selection of the active beam at each point in time. This article presents the use of artificial neural network (ANN) to improve the performance of switched beam smart antenna. The proposed method is based on feed forward backpropagation ANN. In this design, samples of the calibration of the footprint of the base station is mapped to the radiation pattern of Butler matrix (BM) base station antenna arrays. A $$4\times 4$$4×4 BM is designed to implement the developed technique and a digitizer applied to obtain the ANN training data. The results are compared with the existing numerical method and negative selection algorithm based on received signal strength indicator. It is shown that the proposed method exhibits a better switching performance.

Switched Beam Smart Antenna for Wireless Local Area Network

Switched Beam Smart Antenna for Wireless Local Area Network

Advanced Antenna Techniques and High Order Sectorization with Novel Network Tessellation for Enhancing Macro Cell Capacity in DC-HSDPA Network

Mobile operators commonly use macro cells with traditional wide beam antennas for wider coverage in the cell, but future capacity demands cannot be achieved by using them only. It is required to achieve maximum practical capacity from macro cells by employing higher order sectorization and by utilizing all possible antenna solutions including smart antennas. This paper presents enhanced tessellation for 6-sector sites and proposes novel layout for 12-sector sites. The main target of this paper is to compare the performance of conventional wide beam antenna, switched beam smart antenna, adaptive beam antenna and different network layouts in terms of offering better received signal quality and user throughput. Splitting macro cell into smaller micro or pico cells can improve the capacity of network, but this paper highlights the importance of higher order sectorization and advance antenna techniques to attain high Signal to Interference plus Noise Ratio (SINR), along with improved network capacity. Monte Carlo simulations at system level were done for Dual Cell High Speed Downlink Packet Access (DC-HSDPA) technology with multiple (five) users per Transmission Time Interval (TTI) at different Intersite Distance (ISD). The obtained results validate and estimate the gain of using smart antennas and higher order sectorization with proposed network layout.

A small broadband switched-beam Cross-PIFA for m-WiMAX applications

A small broadband and low cost switched-beam smart antenna suitable for mobile WiMAX applications (band class 5–3.5 GHz) is presented in this paper. Present mobile terminal antennas are expected to show increased bandwidth as well as low-loss impedance matching while maintaining low-profile geometry. The proposed structure consists of four planar inverted-F antennas (PIFA) connected forming a cross, sharing the same ground plane, in a configuration designed for symmetrical coverage of the horizontal plane (Cross-PIFA). A custom genetic algorithm (GA) is used in order to optimize the proposed antenna parameters regarding resonant frequency and radiation pattern orientation angle and beamwidth. The optimized antenna exhibits small size (dimensions cm), satisfactory directivity for mobile terminal applications of 3.38 dB over an operation bandwidth of 120 MHz around the central frequency of 3.5 GHz. Simulation and measurement results and parameters range are exposed below followed by the according radiation pattern and variation of the VSWR indicating consistency between design and implementation.

DC–20‐GHz compact SPQT switch for butler matrix switched beam smart antenna system

AbstractA DC–20‐GHz broadband and compact single‐pole‐quadruple‐throw (SPQT) switch for Butler matrix switched beam smart antenna system application has been designed and fabricated on 0.15‐μm GaAs pHEMT process. By adopting inductive high impedance transmission lines in series‐shunt switch topology, the SPQT switch demonstrates an insertion loss of 1.25–3.53 dB from DC to 20 GHz, and the isolation is higher than 22 dB with a compact chip size of 1.5 mm2. The measured output 1 dB compression point (OP1 dB) is 16 dBm at 12 GHz. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2023–2026, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26993

Low-Cost 60-GHz Smart Antenna Receiver Subsystem Based on Substrate Integrated Waveguide Technology

In this paper, a low-cost integrated 60-GHz switched-beam smart antenna subsystem is studied and demonstrated experimentally for the first time based on almost all 60-GHz substrate integrated waveguide (SIW) components including a slot antenna, 4×4 Butler matrix network, bandpass filter, sub-harmonically pumped mixer, and local oscillator (LO) source. In this study, an antenna array, a Butler matrix, and a bandpass filter are integrated and fabricated into one single substrate. Instead of using a 60-GHz LO source, a 30-GHz LO source is developed to drive a low-cost 60-GHz sub-harmonically pumped mixer. This 30-GHz LO circuit consists of 10-GHz SIW voltage-controlled oscillator and frequency tripler. Following the frequency down-conversion of four 60-GHz signals coming from the 4×4 Butler matrix and a comparison of the four IF signals executed in the digital processor based on the maximum received power criterion, control signals will be feed-backed to drive the single-pole four-throw switch array and then the beam is tuned in order to point toward the main beam of the transmit antenna. In this way, the arriving 60-GHz RF signal can be tracked effectively. All designed components are verified experimentally. The proposed smart receiver subsystem that integrates all those front-end components is concluded with satisfactory measured results.

High altitude airborne cellular base stations antenna analysis

Obtaining continual mobile communication coverage over two or more disparate regions from an airborne platform utilizing a deployable cellular base station has proven to be challenging due to the resulting signal spatial structure and signal gain observed from the mobile ground users. A two-dimensional aircraft simulation environment has been developed to evaluate the optimal link budget of an antenna system coupled with a Code Division Multiple Access (CDMA) base station positioned above 45,000 feet in a designated elliptical orbital pattern in an effort to acquire broader and longer communication coverage. This will analyze the signal excess results of both an omni-directional conventional antenna system (CAS) and a switched-beam smart antenna system (SBSAS) with multiple mobile ground users present. Collectively, these results constitute a basis for low-risk implementation for a high altitude airborne deployable cellular base station.

Printed Circuit Switched-Beam Smart Antenna System Using 4x4 Butler Matrix Beamforming Network At The Band (11.25-12.85) GHz

The aim of this paper is to investigate and implement the use of special type of beamformer (the Butler matrix) with an antenna array in a switched beam smart antenna system. This system is designed and analyzed to be used for satellite communication in the band (11.25-12.85) GHz. The system, including a (4x4) Butler matrix and a 4-element microstrip patch antenna array, is completely built using microstrip printed circuit technique for the sake of compactness. The results obtained by simulation and measurement show that this system can produce narrow multibeams in different directions with a wide coverage angle of about 146 and a relatively high crossover level of -3 dB. The resulted beams have directivities range from 9 dB to 11 dB, and half-power beamwidths range from 30 to 42 with relatively low side lobe level of less than -10 dB.

Cross-layer adaptive resource allocation for OFDM systems with hybrid smart antennas

Orthogonal frequency division multiplex (OFDM) has become one of the most popular air-link technologies for future broadband wireless communications. To further improve its bandwidth efficiency and system performance, adaptive resource allocation and smart antenna techniques have been widely used in the OFDM system. However, the use of fully adaptive beamforming in an OFDM system significantly increases the complexity of the medium access control layer design and thus affects the implementation of adaptive resource allocation. A novel cross-layer adaptive resource allocation strategy with hybrid adaptive array and switched-beam smart antennas suitable for the OFDM systems has been proposed. With the help of different smart antennas schemes based on different users&apos; quality of service requirements, the strategy effectively reduces the complexity of adaptive resource allocation in an OFDM system, while still maintaining a satisfactory system performance.

Switched Beam Array Antenna for Sectorized Optimum Power Distribution into Discrete Localities of Rural Area

The technology of Switched Beam Array Antenna for mobile communications has received enormous interest worldwide in recent decade. This type of smart antenna (another type is Adaptive Array Antenna) forms a pattern that adapts to the current radio conditions improving the communication link. The principal reason for applying Switched Beam Array Antenna is the possibility for a large increase in capacity and to introduce new services. The purpose of this paper is to give a performance analysis of Switch Beam Smart Antenna (SBSA) using micro strip patch elements with simulation results obtained by using CST Microwave StudioTM, in KCSTC of IIT Kharagpur.

Development of an Adaptive and a Switched Beam Smart Antenna System for Wireless Communications

This study concentrates on the development of two separate Smart Antenna Systems for the 2.45 GHz ISM band. Both systems incorporate the RF-beamforming method. Each system has the ability to point the beam in a three dimensional space, both in azimuth and in elevation direction. The Switched Beam System adopts a passive network-based beamforming approach, using 2-D Butler matrix topologies. The Adaptive System utilizes the vector modulator method, but only in the azimuth direction, increasing beam-steering accuracy, whereas introducing complexity and cost. The system design is presented for both cases, along with some module design and testing examples. A comparison of the two systems will be also discussed.

Microstrip EHF Butler Matrix Design and Realization

This paper describes the design and realization of an extra high frequency band 8 × 8 microstrip Butler matrix. Operation at 36 GHz is achieved with a frequency bandwidth exceeding 400 MHz. The circuit is implemented on a bi-layer microstrip structure using conventional manufacturing processes. This planar implementation of a Butler matrix is a key component of a switched beam smart antenna with printed antenna elements integrated on-board. Conception details, simulation results, and measurements are also given for the components (hybrid couplers, cross-couplers, and vertical inter-connections) used to implement the matrix.

Performance comparison of a novel hybrid smart antenna system versus the fully adaptive and switched beam antenna arrays

In this letter, we investigate and compare the performance of a newly proposed hybrid smart antenna system with the fully adaptive and switched beam smart antenna arrays. Simulation results show that the adaptive and the proposed hybrid systems have nearly the same performance accuracy, with the hybrid system offering faster tracking time, improved computational efficiency, and a possible reduction in the implementation cost. The comparative study also included measured radiation pattern from a recently developed coplanar waveguide continuous transverse stub (CPW-CTS) antenna.