The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Stacked dielectric resonator antenna from high-k low loss bulk-glass ceramic material have been investigated. Two resonators are stacked with an air gap which has been realized with a low loss foam material. The antenna showed a wide bandwidth with the dimension of 7.7×6.7×2.5mm for the lower dielectric resonator and 8.7×7.7×3.3mm for the upper dielectric resonator. Thus the maximum dimension is 0...
As the positioning accuracy of GNSS systems will degrade in the presence of electromagnetic interference, jamming detection becomes pivotal part in high-precision wireless communication systems which is conventionally accomplished by energy statistics or time-frequency transformation. In this paper, we present the spatial-frequency adaptive processing (SFAP) method which will achieve highly detecting...
A wideband planar array antenna is proposed for Ka-band wireless communication applications in this paper. It consists of several rectangular radiating cavities and a stripline feeding network. Metalized posts are employed to improve the impedance matching. Besides, higher harmonic mode can be suppressed by these metalized posts. A transition from a standard waveguide to a strip line is designed based...
A CMOS true time delay (TTD) chain operating from 1 GHz to 21 GHz is presented for ultra-broadband phased array systems. An eight-stage trombone configuration is employed to provide 3-bit tuning capability. The second order all pass network (APN) is used to construct the gate line and drain line. The adoption of the APN increases the achievable delay while maintaining a compact size. The larger shunt...
This paper presents a new excitation scheme producing dual circular polarization in a class of Dielectric Resonator Antennas characterized by their high profile. The excitation uses a sequential feeding, which produces high quality dual circular polarization over a wide range of angles and results in a polarization bandwidth of 20% to 30% in the Ku-Band. A similar impedance bandwidth can be achieved...
This paper presents the analysis and optimization of a 1 meter single-layer curved contoured beam reflectarray in Ku-band. The curved reflectarray is designed to radiate a contoured beam over a European coverage in both transmit and receive frequency bands for dual linear polarization. For the analysis of the curved reflectarray, the spectral domain method of moments assuming local periodicity is...
This paper presents the structure, radiation patterns and surface current distributions of a dual-polarized patch antenna operating at 10.1 GHz center frequency. The antenna structure is designed for a virtual antenna array which is part of a vector network analyzer based radio channel measurement system. The antenna shows 700 MHz −10 dB impedance bandwidth. The measured isolation between the antenna...
A planar array of 48 parasitic dipoles above a ground plane fed by a single active dipole at 5 GHz, was designed to afford a pencil beam pattern of moderate gain and bandwidth. Measurements agree well with theory.
The adoption of metamaterials in the development of terahertz (THz) antennas has led to tremendous progresses in the THz field. In this paper, a reconfigurable THz patch antenna based on graphene is presented, whose resonance frequency can be changed depending on the applied voltage. By using an array of split ring resonators (SRR) also made of graphene, both bandwidth and radiation properties are...
A 45° linearly polarized slot array antenna with balanced feeding network is proposed in this paper for automotive radar applications. The radiation element consists of one 45° inclined slot and two reflection cancellation vias. The balanced meandering feeding network proposed in this paper is able to achieve a relatively wide impedance bandwidth resulting from the traveling-wave propagation. In addition,...
A shorting-wall loaded metamaterial mushroom array antenna is proposed for bandwidth enhancement and compact design. Owing to the shorting-wall loading, the lower frequency region of the right-handed branch of the composite right/left-handed (CRLH) mushroom structure is exploited. The operating modes of the antenna are investigated. The antenna prototype at 5-GHz band exhibits 26% impedance bandwidth...
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...
A linearly polarized 2×2 patch array fed by a corporate Substrate Integrated Waveguide network for Ku band is presented. The utilization of a corporate topology in the feeding network prevents the antenna from suffering an unintended main lobe tilt dispersion. Nevertheless, the interelement spacing increases, and so does the Side-Lobe Level. Reducing this spacing implies closer discontinuities, such...
We propose a continuous measurement technique which can be used to capture a large number of impulse responses within short time. The response of an acoustic system is continuously captured by a moving microphone, and the instantaneous impulse responses are computed by post-processing. The time-variance due to the movement of the microphone is compensated by employing a recently proposed system identification...
Sparse matrix-vector multiplication (SMVM) is a fundamental operation in many scientific and engineering applications. In many cases sparse matrices have thousands of rows and columns where most of the entries are zero, while non-zero data is spread over the matrix. This sparsity of data locality reduces the effectiveness of data cache in general-purpose processors quite reducing their performance...
The design of an antenna using metamaterials (MTM) for usage in the Terahertz frequency range is presented here. A detailed analysis of the ω-β curves, scattering (S) parameters and radiation patterns is done for a Composite Right/Left Handed (CRLH) transmission line metamaterials designed as a metal-metal (MM) waveguide that incorporates an hour glass slot unit cell structure. An array of the same...
In order to maximize science returns in radio astronomy there is a constant drive to process ever wider instantaneous bandwidths. A key function of a radio telescope signal processing system is to divide a wide input bandwidth into a number of narrow sub-bands for further processing and analysis. The polyphase filter-bank channelizer has become the primary technique for performing this function due...
Carrier frequency and its corresponding direction of arrival (DOA) estimation, at sub-Nyquist sampling rates of narrowband (bandwidth not exceeding B Hz) sources is considered in this paper. We assume M physical sensors arranged in a two dimensional nested sensor array configuration and propose to modify the receiver architecture by inserting an additional delay channel to only the dense sensor array...
In this paper, the characteristics of Reflectarray Antennas printed on convex curved surfaces are analyzed. In particular, results on the radiation performances of different Reflectarrays designed to be mounted on cylinders with different radii of curvature are presented and discussed.
This paper presents a dual-layer Frequency Selective Surface (FSS) that exhibits a wide 4.8 GHz stop-band in 7.76–12.57 GHz frequency range. The FSS demonstrates significant 30 dB attenuation that can be effectively used to shield X-band satellite signals and other systems operating in the band. The unit cell consists of two square-loops, each printed as copper, over the opposite surfaces of FR4 can...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.