In this paper, a low profile 4×8 air cavity fed circularly polarized planar antenna array with high performance for W-band is proposed. This antenna array is composed of two parts, including low loss gap waveguide (GWG) feeding network and high performance magneto-electric (ME) dipole antennas. The antenna elements are fed by the transverse coupling slots right above air-filled high mode cavity with checkerboard structure. Moreover, four-way ridge GWG (RGWG) power divider with transition from ridge GWG to groove GWG is designed to excite the high mode cavity. By properly arranging the position and size of coupling slots, each ME dipoles are excited with in-phase property. Periodic pins are arranged around both the GWG transmission line and the air cavity to create a stop band and resonant frequency. The high mode air cavity is realized by using shorted pins to split the electromagnetic field in shorted-end groove GWG. By this means, the normal GWG feeding technology with GWG power divider and 2×2 air cavity in different layers are combined in a single layer. The transmission loss and substrate loss of this metallic single layer feeding network are reduced, as well as the array profile. Each circular polarized ME dipole antenna are etched on the printed circuit board (PCB) with stable radiation pattern and wide axial ratio (AR) bandwidth performance. The proposed 4×8 planar antenna array is simulated and fabricated to validate the design. A measured 3dB AR bandwidth of 17% and a gain up to 23 dBi has been achieved. The impedance matching is lower than -10 dB over the frequency band with overall boresight gain above 19 dBi.

Objection detection has long been a fundamental issue in computer vision. Despite being widely studied, it remains a challenging task in the current body of knowledge. Many researchers are eager to develop a more robust and efficient mechanism for object detection. In the extant literature, promising results are achieved by many novel approaches of object detection and classification. However, there is ample room to further enhance the detection efficiency. Therefore, this paper proposes an image object detection and classification, using a deep neural network (DNN) for based on high-quality object locations. The proposed method firstly derives high-quality class-independent object proposals (locations) through computing multiple hierarchical segments with super pixels. Next, the proposals were ranked by region score, i.e., several contours wholly enclosed in the proposed region. After that, the top-ranking object proposal was adopted for post-classification by the DNN. During the post-classification, the network extracts the eigenvectors from the proposals, and then maps the features with the softmax classifier, thereby determining the class of each object. The proposed method was found superior to traditional approaches through an evaluation on Pascal VOC 2007 Dataset.

This paper investigates and develops a novel compact broadband and radiation efficient antenna design for the medical internet of things (M-IoT) healthcare system. The proposed antenna comprises of an umbrella-shaped metallic ground plane (UsMGP) and an improved radiator. A hybrid approach is employed to obtain the optimal results of antenna. The proposed solution is primarily based on the utilization of etching slots and a loaded stub on the ground plane and rectangular patch. The antenna consists of a simple rectangular patch, a 50 Ƹ microstrip feed line, and a portion of the ground plane printed on a relatively inexpensive flame retardant material (FR4) thick substrate with an overall compact dimension of 22 × 28 × 1.5 mm³. The proposed antenna offers compact, broadband and radiation efficient features. The antenna is carefully designed by employing the approximate calculation formulae extracted from the transmission line model. Besides, the parameters study of important variables involved in the antenna design and its influence on impedance matching performance are analyzed. The antenna shows high performance, including impedance bandwidth of 7.76 GHz with a range of 3.65Ƀ11.41 GHz results in 103% wider relative bandwidth at 10 dB return loss, 82% optimal radiation efficiency in the operating band, reasonable gain performance, stable monopole-shaped radiation patterns and strong current distribution across the antenna lattice. The suggested antenna is manufactured, and simulation experiments evaluate its performance. The findings indicate that the antenna is well suited for medical IoT healthcare systems applications.

This paper presents a compact broadband antenna for civil and military wireless communication applications. Two prototypes of the antenna are designed and simulated. The proposed antenna is etched on low cost substrate material with compact electrical dimensions of 0.207λ×0.127λ×0.0094λmm3 at 2GHz frequency. The simple microstrip feeding technique and antenna dimensions are involved in the design to attain the proper impedance matching. An optimization of variables is carried out by multiple rigorous simulations. The designed antennas have achieved the broadband impedance bandwidth of 89.3% and 100% at 10dB return loss. The antennas exhibit omni directional radiation pattern at lower resonances and strong surface current distribution across the radiator. The peak realized gain of 5.2dBi at 10.9GHz resonant frequency is realized. Results reveal that the proposed broadband antenna is a better choice for WiMAX, UWB, land, naval and airborne radar applications.

This paper presents the design and development of a new semicircular inverted triangular shaped antenna for 5G millimeter-wave wireless applications. An alternate-mixed approach based on cavity, slots and loaded stubs is employed in the designed antenna lattice. The suggested antenna structure is formed by a radiator, partial defected metal ground plane and a 50 Ω coplanar waveguide. The proposed antenna resonated at multiple frequencies by the setting up of the proper dimensions and locations of the rectangles, elliptical cut slots and cavity stubs. Furthermore, a parametric analysis is carried out to examine the antenna’s effectiveness and impedance-matching controls. The proposed structure is realized on the low-cost RT/Duroid Rogers RO3010™ laminate with an overall small size of 1.381λ₀ × 1.08λ₀ × 0.098λ₀, where λ₀ represents the wavelength corresponding to the minimum edge frequency of the 23 GHz at 10 dB impedance bandwidth of the antenna. The antenna’s key characteristics in terms of bandwidth, gain, radiation patterns and current distribution have been investigated. The antenna exhibits high performance, including an impedance bandwidth of 19 GHz ranging from 23 GHz to 42 GHz, results in 58.46% wider relative bandwidth calculated at 10 dB scaled return loss, a peak realized gain of 6.75 dBi, optimal radiation efficiency of 89%, stable omnidirectional-shaped radiation patterns and robust current distribution across the antenna structure at multiple resonances. The designed antenna has been fabricated and simulation experiments evaluated its performance. The results demonstrate that the antenna is appropriate and can be well integrated into 5G millimeter-wave wireless communication systems.