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This paper presents a low-profile antenna based on the use of a multilevel metallic hole array (MHA). The antenna is fed by an open rectangular waveguide placed at a short distance from the MHA. The array operates as a frequency selective surface (FSS) to enhance the directivity of the rectangular aperture within the frequency band of operation of the FSS. The small distance between layers gives the...
We present a reconfigurable transmission metasurface based on microfluidic system. As a proof of concept, the focal length of the metasurface is tuned from near-field region (1 λ) to far-field region (18 λ).
This article reports the findings of a compressive infrared sensing approach for arm gesture acquisition and recognition. The spatial-temporal changing motion information are intrinsical clues for determining the semantics of gesture, which can be considered as a sparse spatial distribution compared with the sensing region. We first built a database of dynamic arm gestures with writing Arabic numerals...
We developed a polarization dependent reactive mesogen lens array by using both bottom-up and top-down alignment method for 2D/3D switchable 3D device systems like auto-stereoscopic display and light field camera.
A time-multiplexed two-directional sequential projection scheme (TTSP) is proposed and demonstrated to implement a viewing-angle-enhanced integral imaging display system. The main idea behind the method is sharing of the same image screen to display two sets of directional elemental images (DEIs) in a time-multiplexed sequential projection manner.
The synthesis of a graded-index isotropic radome for the miniaturization of linear arrays is addressed. The combination of a System-by-Design paradigm with a Quasi-Conformal Transformation Optics - Source Inversion technique is proposed to enable the reduction of the array aperture while also avoiding anisotropic materials within the synthesized lens. To achieve this goal, the QCTO part of the problem...
For fast design of Rotman lens the symmetry plane is used to reduce the structure size, but solved twice. One solution with the symmetry plane as electrical wall and the second with magnetic wall are used. Then process the s-parammeters from both solution to obtain the s-parameters for the original lens for even or odd number of ports. A wideband Rotman lens for 6–18 GHz and beam scanning capability...
A parametric study on a periodic structure made of thin dielectric cylinders is performed. A Luneburg's lens is chosen for implementation since its medium is non-homogenous. Design rules on the periodic structure's unit cell size are determined and the material effect on the lens performance in the near and far fields is analyzed.
Quasi-conformal transformation optics (QCTO) provides a practical approach to design nonmagnetic broadband medium for electromagnetic devices, here we present a novel hybrid method of QCTO with array synthesis, and apply it to conformal phased array antenna (PAA) design which makes the complex conformal PAA can behave like a geometrically different array with wide scanning range when surrounded with...
This paper presents a V-band double-sided, printed bow tie antenna which exhibits 49% bandwidth (46∼76 GHz). The antenna is fed by a microstrip transmission line for easy impedance matching. The simple structure and the small antenna are suitable for low cost fabrication, easy circuit integration, and phased antenna array multi-frequency applications.
This paper presents the design and measurement results of on-chip differential fed semi-circular slot antenna. Slot antenna allows easy metal density adjustment to comply with design rule requirement on standard CMOS process. This antenna works with a triple-pushed Colpitts voltage control oscillator (TPCVCO) to form a monolithically integrated 2×4 coherent source array operating at 0.54–0.55 Tera-Hertz...
This paper presents a novel substrate integrated waveguide (SIW) for X-band sensing applications. It employs a SIW Rotman Lens (RL) as a beam switching network. A prototype lens is designed with 7 beam ports and 9 array ports. The simulated results around the frequency of 10-GHz demonstrate the validity of the proposed design and scanning capability over (−24°, +24°). Throughout this paper, the design...
This paper emphasizes on the emergence of Meta-materials in the field of antenna designing. For enhancing the performance of the antenna in terms of various parameters viz. gain, directivity, main lobe and side lobe levels, bandwidth; Meta-materials (MMs) are used as an uniform flat lens along with the antenna. A novel ‘U’ shape slotted patch antenna & its array of 2×2 is designed for 2.4 GHz...
A hybrid of spherical modal analysis and geometrical optics based computation of EM fields over a near field spherical surface surrounding the lens antenna is presented. The near field of the primary radiator is obtained from a spherical modal expansion (SME) of its far field pattern. The principal component of a requisite number of spherical modes are then treated as co-located sources radiating...
This paper presents a new approach to achieve a beamforming network for 60 GHz applications. The proposed technique consists of a printed bow-tie antenna with end-fire radiation type integrated by an array of metamaterial lens. Embedded in the elevation-plane of the printed bow-tie antenna, an array of metamaterial unit-cells with low-index is proposed to obtain a beam-tilted angle of 22 degrees with...
We propose two novel beam steering lenses by metamaterials. The first one is a low graded index lens that can be used for beam compression and collimation. The refraction index profile of this lens is Mikaelian's lens with extremely low refraction index. We design a metal-wire array to realize this lens. The second lens is designed for extending the scanning angle of a phased array antenna by Transformation...
A Single-mode 24-fiber connector with GI fiber-lenses is developed. The lenses make it possible to adopt MT-connector based guide-pin-alignment. Insertion loss of 0.54dB on average and loss variation less than 0.08dB under temperature cycling is achieved.
We report on deterministic femtosecond multi-filamentation in fused silica by encoding a diffractive microlens array into a spatial light modulator. The efficiency and focal length of each microlens are electronically controlled. Even for an input inhomogeneous irradiance distribution, this allows for a precise control of the energy coupled to the filaments and the spectra of the generated supercontinuum...
Diabetes is a group of diseases in which the body has trouble regulating blood glucose. As concern for diabetes grows, the need for automated and accurate methods to monitor nutrient intake becomes essential for managing dietary. The challenging problem of the image-based dietary assessment is how to estimate food volume from a photograph taken with a camera. We present a design with aspherical surface...
The proposed holographic Shack-Hartmann wavefront sensor can measure a wavefront aberration with large dynamic range. It is realized by introducing a holographic optical element and pattern matching technique. To confirm the flexibility of the sensor, measurements of the wavefronts with various aberrations are numerically demonstrated.
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