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In this paper, a hybrid genetic algorithm (GA) is proposed for thinning a two-dimensional planar array by combining the conventional GA with moving least squares (MLS). This enhances the convergence rate and the global search performance. The MLS method is used to estimate local interpolation functions from non-uniform sample data (the population and the value of the objective function in the GA), and to find new and better populations from the interpolated functions. By incorporating these improved populations into the next generation, the MLS-GA achieves improved search performance of the global optimum and a faster convergence rate compared to conventional GA alone. Moreover, a nonlinear chirp function is used for an efficient thinning design. To verify the proposed MLS-GA, it is applied to a test function and the results are compared to that of the GA. The algorithm is then applied to thin an array with a rectangular grid and circular boundary. The design objectives are to minimize the peak side-lobe level and gain loss while satisfying a given thinning coefficient and to compare the results with the GA.

The accurate estimation of clutter covariance matrix (CCM) is essential in designing a radar detector/filter to suppress sea clutter. This estimation might not be easily accomplished because of the scarcity of valid training vectors adjacent to the range cell under test (CUT). We propose a new CCM estimation algorithm that is derived by modeling time-series clutter returns into a clutter Doppler spectrum in the frequency domain and exploiting mutual independence among spectral components. To justify its excellence over the conventional sample covariance matrix (SCM) algorithm, we design two filters—a maximum signal-to-interference-plus-noise ratio (SINR)-based filter and a whitening filter—that use the estimated CCMs and compare their performance in a numerically simulated sea clutter scenario. Comparisons are made by showing the eigenvector spectra of the estimated CCMs and the frequency responses and outputs of the filters. Moreover, SINRs at the target Doppler bin are examined and compared with a theoretical, analytically derived SINR.

This study presents a novel computationally efficient method for estimating the direction of departure (DOD) and direction of arrival (DOA) of targets and discriminates the DOA of jammer signals for a bistatic multiple-input, multiple-output (MIMO) radar system. Using properly designed projection filters, the proposed method replaces expensive exhaustive two-dimensional angle search with several one-dimensional angle search algorithms. The proposed method estimates DOD–DOA pairs of targets and discriminates jamming signals successfully regardless of the jamming signal strength. The performance of the proposed method is confirmed by simulation results.

A knowledge-aided space-time adaptive processing (STAP) is a quite useful technique to suppress non-stationary and heterogeneous clutter. It estimates a covariance matrix by combining a conventional covariance matrix based on secondary data with a synthesised one by prior information. A new combining method is presented, where weight vectors, rather than constant weights, are used to combine two covariance matrices. In this method, the weight vectors are derived in a way to maximise clutter-to-noise ratio of the combined covariance matrix. A numerical simulation is conducted for a bistatic radar scenario where clutter non-stationarity and heterogeneity can be assumed and the performance of the proposed method is demonstrated in terms of clutter suppression and target detection.

A novel dual-band compact patch wireless fidelity (Wi-Fi) antenna using μ-negative (MNG) transmission lines (TLs) for the smart helmet is presented. In the smart helmet scenario, rescue agent is able to communicate with the other rescue agents, control centre, and drones via the helmet by Wi-Fi dual bands. For the smart helmet communication, the antenna, which consists of two MNG-TL loops located on the outside and inside, is devised. The dual-band corresponds to the zeroth-order resonance (ZOR) and second-positive-order resonance (SPOR) of the outer MNG-TL. The ZOR frequency of the outer MNG-TL is near the Wi-Fi 2.4 GHz band, and the SPOR frequency of the outer MNG-TL, excited by the coupling between the inner and outer MNG-TL loops, is the Wi-Fi 5 GHz band. The prototype of the proposed antenna has been fabricated and measured. The bandwidth of the antenna includes Wi-Fi 2.4 and 5 GHz bands with high radiation efficiencies of >49% and a compact size of 27.6 mm × 27.6 mm × 1.27 mm (1/4.5 λ × 1/4.5 λ × 1/98.4 λ at the lowest operating frequency).

This paper presents a compact antenna geometry to realize an radio frequency (RF) system in package (SIP) and discusses an antenna-integrated package for an IEEE 802.11a application. The proposed compact antenna is similar to a modified U-shaped slot antenna; however, its electrical properties are quite different. A fabricated antenna demonstrates bandwidth of 180 MHz at a center frequency of 5.8 GHz, and it may be used to implement antenna-integrated packages. An antenna-integrated package is proposed consisting of the antenna placed on the top surface, internal space for integration of other IC components, a conducting layer placed between the antenna and the internal space, and finally a bottom layer. In addition, from the parametric studies it is found that the size of the package, dielectric thickness of the antenna, package height, and the number as well as the position of via holes, are critical factors of antenna characteristics

This paper presents the design of a multi-standard NTSC/PAL video encoder. The encoder converts International Telecommunication Union-Recommendation (ITU-R) BT.601 4:2:2, ITU-R BT.656 or RGB inputs from various video sources into National Television Standards Committee (NTSC) or phase-alternate line (PAL) TV signals in both S-video and composite video baseband signals (CVBS). The encoder adopts multiplier-free structures to reduce hardware complexity. The hardware bit width of programmable digital filters for luminance and chrominance signals, along with other operating blocks, are carefully determined to produce high-quality digital video signals of 1 least significant bit (LSB) error or less. The proposed encoder is experimentally demonstrated by using the Altera APEX20K600EBC652-3 device.

In this paper, we propose a three-dimensional real-time disparity system that converts the locations of objects into the gray-scale image by using two images incoming through stereo cameras. While measuring the similarity for the images, the proposed system adopts the vertical strip structure for a real-time processing. The proposed system is able to process 15 frames per second (fps) and display the resulting disparity images with 30 fps on the TV sets. The system is designed by using the VHDL. It is also experimentally demonstrated by using the Altera APEX20K1000EBC652-3 device.

Presented is a novel monopulse estimator that uses the inverse function of a monopulse ratio (MR) curve of the maximum likelihood (ML)-based monopulse estimator. The proposed estimator exploits the fact that the ML-based MR curve is approximated by one tangent function. The proposed estimator works in two steps, in which the ML-based estimator is applied first and then its output is corrected by the inverse function of the MR curve of the ML-based estimator. Its derivation is presented, in addition to simulation results showing that it outperforms the conventional ML-based estimator.

Radio frequency identification (RFID) is one of the most attractive and futuristic technologies that can identify an object or person wirelessly, using electromagnetic radio waves. In a multiple reader RFID system, the reader interference problem is a very common phenomenon. Efforts are required to minimize this problem as performance, speed and reliability of the entire system highly depends on our ability to solve this problem efficiently. A simple adaptive beam-forming technique is proposed for solving the reader interference problem in a multiple reader RFID system. This new approach is able to effectively generate deep nulls at the direction of interference and respond to the direction of our desired signal. Simulations are carried out to evaluate the performance of our adaptive beam-forming approach and the results confirmed that, the proposed method can adaptively generate a high gain beam to the desired signal direction to acquire and track the signal completely, and it can generate deep n...