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An active millimeter wave imaging system with sparse antenna array for security inspection is introduced in this review. Several key parts and related techniques of the imaging system are explained and numerical results are provided.
Design of a control module for millimeter wave imaging system based on FPGA is presented in this paper. There are four parts in the module: scanning control module of antenna array, data acquisition and storage control module, ethernet transmission control module and mechanical scanning platform control module.
Massive multiple-input multiple-output (Massive MIMO) is acknowledged as a key technology for the 5th generation (5G) of wireless communication systems, which theoretically proved to be of higher throughput, better robustness, superior spectrum- and energy- efficiency. A reliable and realistic channel model serves is the enabling foundation for practical design and testing of communication systems...
In our previous publication, we have designed a ground penetrating radar (GPR) system with and antenna array for in-situ estimation of the thickness and dielectric permittivity of the asphalt pavement. In this paper, we change the work mode of the GPR antenna array from the ground-coupled mode to the off-ground one, accelerating the data acquisition speed required for highway inspection. The GPR antenna...
This paper presents an analysis of the Multiple-Input Multiple-Output (MIMO) capacity based on channel sounding measurements in a residential house. Specular and dense multipath components are estimated from the channel sounding data with the RiMAX maximum-likelihood algorithm. These multipath channels serve as input for the capacity calculations. Specifically, capacity calculations are done for a...
This paper introduces a new direction of arrival (DOA) estimation method for Doppler radars with Multiple-input multiple-output (MIMO) systems, which have been used in various applications, for example, detection and classification of indoor human activities. To improve DOA estimation accuracy, the temporal-spatial virtual array based on Doppler shift of a moving target has been proposed; hereafter...
In this paper, we study the achievable multiplexing gain of millimeter wave (MMW) line-of-sight (LoS) multiple-input multiple-output (MIMO) channels with non-uniform linear antenna arrays (NULAs) at both the transmitter and receiver. We first present an analytical characterization for the asymptotic channel eigenvalues with arbitrarily deployed NULAs. Then, aiming at achieving an effective multiplexing...
Performance of array processing algorithms is directly determined by the number of array elements. Processing of data from a large number of receive array elements involves a large number of receivers, resulting in high cost and complex implementations. In many practical applications, a large number of receiving antenna elements is available, however, the number of receivers is limited due to their...
This paper conducts theoretical study on employing phase-conjugation antenna array to beam microwave power from satellite to earth in the context of space solar power (SSP) applications. Our analysis reveals that, the phase-conjugation array must have aperture dimension greater than 1 km × 1 km in order to be applicable to practical SSP systems. Moreover, antenna array with such a large size does...
In this paper, a 24 GHz to 33 GHz frequency-modulated continuous-wave radar (FMCW) system is proposed. Beginning in the range of 2 GHz to 2.7 GHz, three separate multiplication stages bring the frequency band to between 24 GHz and 33 GHz. The system is integrated with a set of planar Yagi antennas. A single planar Yagi antenna is included on the transmit side, while four antennas in a steerable uniform...
Many companies face issues today in locating their assets and inventories in storage racks. In this study, we explored the use of passive UHF RFID for locating relative positions of items on storage racks. The storage rack with UHF RFID localization function is named as smart rack in this study. This paper addresses the technical issue of how to make use of the reference RFID tag signals to improve...
Electromagnetic fence designs have potential to provide border security especially for military tasks. In this paper, design, simulation and experimental results of a microstrip patch antenna array which may be suitable for an electromagnetic fence application at C-band are presented. Moreover, an experimental demonstration of the effect of a person on the signal propagation between the transmitter...
In order to avoid eavesdropping, beamforming can be used not only to induce artificial noise or jamming signal to an eavesdropper, but also transmit desired signals to a legitimate user (or sensor) from an access point (AP) equipped with an antenna array. In this paper, with proper power allocation, we show that beamforming under a rich scattering environment can guarantee a certain secrecy rate with...
Orbital angular momentum (OAM) based on uniform circular array (UCA) has been proposed to achieve larger channel capacity in radio frequency. There have been many researches on theoretical analysis and practical antenna design of UCA. However, there have been few studies on the characteristics of OAM signal based on UCA considering spin angular momentum. In this paper, we have proposed two UCA architectures...
This work concentrates on design of antennas in micrometer range that corresponds to infrared frequencies. The antenna is made to resonate around 10 micrometer range, which is the peak of IR radiations reaching the earth's surface. Various studies of different antenna designs were carried out and Bow-Tie antenna is selected as the final design based on its geometrical features that enhance the voltage...
A beamformer system for a linear two-element interferometer aligned east-west is implemented. Two phase shifters based on a delay line technique, using coaxial cables and a diode network for selection and deselection of phases, are implemented at a centre frequency of 10.7 MHz. Each phase shifter consists of 6 bits, that are controlled digitally using an Arduino board, to produce 64 discrete phase...
Recent works have demonstrated the feasibility of microwave imaging using compressive techniques, exempting the use the of active delay lines, phase shifters, or moving parts to achieve beamforming. With this method, waves are coded in a passive way by a compressive device to reduce the complexity of the transmitter and/or receiver chains of the telecommunication and radar systems requiring beamsteering...
An adaptive beam forming algorithm with antenna array model based on quantum-behaved particle swarm optimization (QPSO) is proposed for improving existent problems of limited beam modulation, unsatisfactory side lobe suppression and poor adaptability. By adjusting beam direction with matrix-weighting, optimizing initial phase and radius of the antenna array, and by tracking user intelligently with...
Giant Ukrainian Radio Telescope (GURT) is a low-frequency one with active phased antenna array, which is being built in Ukraine in addition to the existing UTR-2 radio telescope. In this paper we consider the signal-to-noise ratio in active antenna, which is used as an element of GURT radio telescope antenna array. The sensitivity of the element mainly determines the sensitivity of not only the entire...
In this paper, we focus on a throughput increase in multiantenna Radio Frequency Identification (RFID) systems. We propose a physical layer collision recovery receiver with spatial filtering. Our goal is to decrease the number of tags involved in a collision by postprocessing received signals and cancelling tags from certain directions of arrival. To achieve this, we divide the reader's area in sectors...
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