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In estimating DOA of incident waves with high accuracy, we often have to take into consideration the angular spread of each wave due to reflection, diffraction, and scattering. As a method of estimating DOA and AS simultaneously, SAGE-DOA-Matrix method was proposed which uses DOA-Matrix method along with SAGE algorithm. In this paper, we further improve the estimation performance of the method by...
In this paper, we demonstrate a waveguide slot array antenna by integration of T-shaped filters using the diffusion bonding of laminated thin metal plates. The excellent performance of the T-shaped filter has been experimentally verified by the in-band transmission and the out-of-band rejection of the fabricated antenna.
A system composed of a grid array antenna (GAA) and parasitic monopoles is analyzed. The analysis is performed using an integral equation with the method of moments to reveal the radiation pattern, axial ratio, half-power beam-width and gain. It is found that the parasitic monopoles contribute to transforming a linearly polarized beam from the GAA into a circularly polarized beam. It is also noted...
In this paper, we study performance of a simple electromagnetic band gap (EBG) resonator antenna (ERA) that has a composite all-dielectric superstructure and is excited by a small sparse array. The cavity of the antenna is excited by a 2×2 array of waveguide fed slots with an inter-element spacing of 1.8λo. The ERA exhibits high gain with an excellent directivity bandwidth of around 20%. The proposed...
Blind signal separation techniques using array antennas are expected to bring many advantages in the radio monitoring system. In several techniques, Independent Component Analysis (ICA) attracts much attention because of its convenience and effectiveness. In this paper, we focus on SOBI algorithm in ICA and examine the performance under the effect of mutual coupling of array elements.
The authors have proposed a non-contact vital sign detection method using a microwave. In general, the body surface movement due to respiration is significantly larger than that of heartbeat, and this obstructs heartbeat detection. In this paper, we propose the microwave heartbeat detection method by suppressing the respiration component. Measurements were carried out in a multi-path environment,...
A compact-range wireless access system in the 60 GHz-band has been proposed for multi-Gb/s data transfer. Large array antennas adopting in the transmitter operate in their near-field regions, and provide us with a large communication zone and a pure propagation environment. However, intersymbol interference (ISI) may significantly degrade the system performance especially when the receiver is close...
Reconfigurable antennas capable of radiating in only specific desired directions increase system functionality in applications like direction finding and beam steering. This paper presents the design simulation, fabrication and measurement of a horizontally polarized, direction reconfigurable Vivaldi antenna, designed for the lower-band UWB (2–6 GHz). This design employs eight circularly distributed...
A substrate-integrated-waveguide (SIW) aperture-coupled antenna array is presented at millimeter-wave band. The antenna design is located on the upper part of the substrate fixed with a half size of Samsung Galaxy Note 4. The antenna array has been implemented with the multilayer structure which is realized by stacking three substrates and a copper plate. The simulated results are validated with the...
A concept of integrated feeding network designated for excitation of dual-linear polarization in series-fed microstrip antenna lattice has been proposed. The presented feeding network is composed of two Wilkinson power dividers and two 3-dB/90° directional couplers acting as a transmission-line crossover. As it has been shown such a compact network can be easily integrated with the recently developed...
A millimeter-wave cylindrical conformal array with 120° flat-top broad beam and a stable 30° downward tilted-angle is demonstrated, fabricated and measured in this paper. A 32-element longitudinal slots array antenna is selected as the radiating element of the cylindrical conformal array, which is wrapped around the cylindrical in the circumferential direction. A 1-to-8 unequal power divider and a...
A Fabry-Pérot cavity antenna with extended 3dB gain bandwidth is presented in this paper. The proposed structure consists of a rectangular-patch microstrip antenna, on top of which a planar partial reflective surface (PRS) is mounted. Two periodic planar structures, i.e. metasurfaces, with different unit cells are printed on both sides of a 1.5mm-thick Rogers 5880 substrate, forming a novel PRS. It...
Narrow bandwidth is a challenging problem for designing platform-mounted electrically small antennas in the high-frequency (HF) band. In this paper, we demonstrate a process that can be used to improve the bandwidth of a platform-mounted HF antenna or antennas by taking advantage of the presence of the platform. Specifically, we examine a simplified model for the Expeditionary Fighting Vehicle (EFV)...
This paper presents a two layer 2×2-slot element as a sub-array for 60 GHz planar array antenna based on gap waveguide technology. The proposed element consists of 2×2 slots in a gap waveguide cavity where the cavity is fed through a coupling slot from a ridge gap waveguide corporate-feed network in a lower layer. The 2×2-slot sub-array is numerically optimized in an infinite array environment. The...
A superdirective array of electrically small dipole radiators can effectively be used as a compact and lightweight first-order probe (a directive antenna radiating predominantly spherical modes with the azimuthal index |μ| = 1) in spherical near-field antenna measurements at low frequencies. This contribution shows that a very narrow frequency bandwidth peculiar to superdirective antennas can be extended...
A concept of sidelobe level reduction in multibeam antennas fed by 4 × N Butler matrices has been extended on multibeam antennas with broadside beam. It has been shown that by adding in-phase power dividers at the output of a Butler matrix ensuring ±90°, 0° and 180° differential phases and by increasing the number of radiating elements a significant sidelobe reduction can be achieved, similarly as...
We proposed silica-based post-wall waveguides (PWWs) with input and output (I/O) transitions from microstrip line for 71–76 GHz and 81–86 GHz, respectively. The PWWs were designed so that their reflection keeps lower than ™20 dB at the aimed frequencies. They were fabricated in silica substrates and the performance was measured. Realization of the bandwidth of 23.6% was confirmed at the lower band...
This paper presents a new collinear antenna array that can realize high omnidirectional gain at 30GHz band. The array are formed by two stacked biconical antenna elements fed parallel through a balun, and each element can produce an omnidirectional gain of around 9.5dBi. The measured ™10-dB impedance bandwidth of the antenna is 26.2–30.2GHz. Within the bandwidth, the antenna achieves a high measured...
A broadband beam steering continuous transverse stub planar array fed by the parabolic reflector of substrate integrated waveguide (SIW) is proposed in this paper. The beam steering function could be realized by mechanically moving the H-plane SIW horn straightly along the direction of the stub. A 16-element array is simulated to validate the design. The simulation results show that the relative bandwidth...
A circularly polarized antenna array for E-band application has been designed, fabricated and measured. The antenna array is fed using substrate integrated coaxial line (SICL) technology, which can be realized by low-cost PCB process in millimeter frequencies. The simulated and measured S11 is below ™10dB from 71GHz to 76 GHz. And the simulated and measured results show that both the gain of more...
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