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This paper proposes a small CRPA array with frequency-insensitive properties. The array consists of seven elements, and each element is composed of upper and lower circular loops that are designed to resonate at 1.575 GHz and 1.227 GHz, respectively. The lower loop is fed by the hybrid chip coupler, and the upper loop is electromagnetically coupled for a frequency-insensitive feeding mechanism. Due...
A coupling reduction method is proposed by using stacked electromagnetic band gap (EBG) structure for a two-element antenna array. The stacked EBG is a periodic multilevel layered electromagnetic band gap structures (PML-EBG). The PML-EBG is set in the middle of two identical patch antennas with distance of 0.13λ. The proposed antenna operates at 2.55GHz. A good isolation is achieved by the use of...
Series-fed antenna arrays always experienced beam-squinting issue. Zero group delay(ZGD) element providing a potential solution for squint-free beamforming in series-fed antenna arrays. In this paper a novel synthesis approach for dispesionless optimized zero group delay line is proposed for the first time. Polynomial synthesis based approach is adopted which provides more design flexibility. Complete...
This paper focuses on tracking and objects identification by means of High Frequency magnetic coupling RFID (Radio Frequency IDentification) at 13, 56 MHz. The coil of the used RFID tags corresponds to 1.9% of the reader coil surface (120×160 cm2). To increase the size ratio between the two coils, we proposed the use of multiple twisted loops antenna. The reader antenna is consequently divided into...
DESHIMA (Deep Spectroscopic High-redshift Mapper) is an instrument aiming at efficiently making spectroscopic redshift measurements of sub-mm wave galaxies (SMGs), thereby providing about the formation and the evolution of stars and galaxies. The aim of this work is to provide a preliminary study into the design of a wideband leaky lens antenna coupled quasi-optical system within a 1:3 bandwidth....
Massive Multiple-Input Multiple-Output (MIMO) has become one of the key technologies for future mobile communication systems. Although there is a variety of potential benefits, unresolved implementation issues of massive MIMO are manifold. In this work, we consider the issue of mutual coupling in large antenna arrays. A known matrix model that describes array coupling effects is considered. This coupling...
Arrays of coupled split ring resonators (SRRs) capable of carrying slow short-wavelength magneto-inductive waves have been shown to support the rapidly varying current distributions required for superdirectivity. However, the superposition of both electric and magnetic dipole resonance modes contributing to radiation of SRRs challenge pure physical intuition in the selection of the optimal dimer configuration...
It is proposed to use half-round fixtures in order to excite straight-sight vertical slots in a narrow wall of a rectangular waveguide. The advantage of their use is this: lower level of cross-polarization radiation compared to variable slant slots, simplicity of parameters calculation, easy design performance and low reflection index. Variable conductivity is achieved by means of fixture fixture...
Sparse source reconstruction is an effective method to find the radiation source from the near field scanning. Therefore, it is attractive to use sparse source reconstruction to locate failing elements in a failing array. This paper presents recent advances of sparse source reconstruction for near-field-based array diagnosis. First, fundamental formulation of near-field-based array diagnosis using...
Two problems of achieving the required decoupling in antenna systems have been studied: in the first problem, the required isolation was achieved by changing the phases of the PRS currents, in the second case due to the change in the parameters of the impedance decoupling structure.
Millimeter-wave (mm-Wave) Massive Multiple Input Multiple Output (MIMO) at 60 GHz is a candidate of advanced wireless communications for indoor environment. Mm-Wave massive MIMO antenna with lower frequency with sectoring technique has been proposed in previous research. Also dual polarized configuration for MIMO in lower frequency and lower number of antenna. Massive MIMO at 60 GHz mm-Wave is not...
A novel method allowing for reduction of coupling between vertically placed radiating elements in antenna arrays has been proposed. It has been shown, that appropriate offsetting the antenna array elements from the array symmetry axis allows to improve isolation between adjacent elements, which results in improvement of the obtained radiation pattern. The theoretical investigation has been performed...
The problem of Angle-of-Arrival estimation of multiple sources in the presence of mutual coupling is addressed. The presence of unknown mutual coupling between antenna array elements is known to degrade the performance of direction-finding algorithms. We first present a result explaining why some traditional methods, that estimate Angles-of-Arrival (AoAs) of multiple sources in the presence of mutual...
A recently published paper presented a novel concept for obtaining frequency reconfigurable behavior by combining multiple antenna elements and weighting the feed signals for each element. In this paper, we clarify some concepts presented in that paper and analyze the antenna structure in more detail.
A mechanically reconfigurable waveguide-slot single radiating element is presented. The tuning mechanism consists on three metallic screws introduced through the bottom wall of the feeding waveguide. The insertion length of the tuning screws and the distance to the slot are used to control the radiated signal as well as to maintain a good input matching response. Several prototypes with different...
A low-profile and decoupling dipole antenna array is achieved by combining patch type meta-surface with proposed parasitic cells. Based on the moment method analysis results, it is clarified that proposed parasitic cells can suppress mutual coupling of dipole antennas without additional impedance. In addition, the maximum decoupling effect of 13.3 dB is achieved.
An effective technique for reducing the mutual coupling between mm-wave dielectric resonator antennas (DRA) using a novel metasurface is investigated and presented. This is achieved by embedding a metasurface wall between the two DRAs, which are placed in H-Plane. Using the proposed metasurface, the TE modes of the antenna become orthogonal which reduces the mutual coupling between the two DRAs. The...
The inter-element distance in superdirective arrays is usually very small and hence the mutual coupling is considerably high. Consequently, these arrays present relatively low efficiencies. In this paper, we propose using decoupling techniques for reducing the mutual coupling, and hence increasing the efficiency, in this kind of arrays. The concept is proven by full wave simulations of two different...
A new attractive elementary cell is proposed for 1-bit and 2-bit transmit-arrays in X-Band, where the wideband and low loss characteristics are crucial. The proposed unit cell consists of two identical square patch antennas include C-loop slot and interconnected in their centers by a metalized via hole. The unit cell exhibits a simple three-layer metallic structure and allows standard printed-circuit...
Graphene-based plasmonic nano-antennas are envisioned as an enabling component for compact communication systems in the Terahertz (THz) band (0.1–10 THz). Despite their high efficiency and due to their reduced size, the total radiation power of individual nano-antennas is expectedly very low. To overcome this limitation, plasmonic nano-antenna arrays are proposed. In this paper, the performance of...
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