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A novel X-band unit cell structure with improved bandwidth performance for single-layer microstrip reflectarray antenna is proposed. The new element structure consists of two circular rings, each with a pair of gaps, and two phase-delay lines are attached to the outer ring to provide the required phase shift. A 9×9 center-fed reflectarray antenna operating at 10 GHz is designed to validate the broadband...
The paper presents a novel cascaded folded waveguide traveling wave tube (FW-TWT) interacting with two beams operating at TE20 mode. This cascaded structure is constructed by two sections. The downstairs section interacts with the two beams to amplify the signal initially. It also provides the upstairs section with small input power. The upstairs section continues to amplifying the signal. Both the...
We have proposed an interaction circuit of eight cavities for a W-band broadband extended-interaction klystron (EIK). The W-band broadband EIK with a 0.5 A, 17 kV beam is simulated both by 1D-AJDISK and 3D-CST PIC simulation code. The results of AJDISK and CST-3D PIC simulation indicate the peak RF output power of 1.4 kW, 3-dB instantaneous bandwidth of 0.8 GHz. The research can promote the development...
This paper discusses the loaded Q-bandwidth of non-Foster matched electrically small antenna(ESA) in the VHF/UHF band. The non-Foster circuit (NFC) is based on resonant tunnel diode (RTD) operating at negative differential resistance (NDR) region. A low quality factor (Q<1) across the matching bandwidth has been attained to ensure that the energy losses are minimum within the resonant circuit....
This work presents a solution for matching electrically small antennas in broadband and multiband applications where efficiency levels should not be very low. To do this, a two-port antenna concept is introduced to design an embedded LC structure in the architecture of the antenna. Simulation results are presented in the upper part of the VHF band (80–180 MHz) and in the lower part of the UHF band...
Impulse radio has been historically proposed for short-range Ultra-Wideband (UWB) transmission. However, thanks to the well-known properties of easy generation and robust detection in presence of linear and nonlinear distortions, such kind of waveforms have been considered also for long-range broadband satellite communications, in particular exploiting Extremely High Frequency (EHF) bands (Q-V band...
A compact broadband dual-polarized patch antenna operating from 1.71 to 2.69 GHz for multi-functional services is presented. It has the total size of 100×100×22 mm3 (0.74λ0×0.74λ0×0.16λ0). Four fork-shaped probes are used to feed a square patch antenna to enhance the impedance bandwidth. A pair of broadband 180°-baluns designed using metamaterial transmission lines (MM TLs) is used in the feeding...
A broadband impedance transformer is proposed for microstrip realization and to release the tight gap size (30 pm) required for coupled-stripline. Design curves of the transformer are obtained by solving the analytical equations derived from the transmission line theory. Two transformers are fabricated and measured. One is designed for a 1:2 ratio and return loss better than 30 dB over a fractional...
A large-aperture low-sidelobe broadband wide-angle scanning system based on completely overlapped subarrays has been presented. The subarray ports use 40-dB Taylor distribution and elements use uniform excitation. A large-aperture array having more than 16 subarrays have an exactly low-sidelobe Taylor pattern. Within a certain range, the bandwidth has linear correlation with subarray size. A smaller...
A printed planar microstrip patch antenna with pattern reconfiguration of total size 50×49.72mm2 is proposed. The antenna features a rectangular patch which is inset fed by a microstrip transmission line and enclosed in a ring. A partial ground plane and three pin-diodes are used to achieve the reconfigurability performance. The radiation pattern can be switched between an omni-directional pattern...
Here we are proposing the work on Optimization of Broadband modified Psi slot Patch Antennas for USB dongle and 4G Applications which was basically designed for 2.4GHz and optimized the results for increasing the performance parameters bandwidth as well as gain with incorporating proximity feeding techniques in addition with extra slots. All the physical parameters have been optimized in order to...
Broadband technologies are playing a very significant role in the information exchange world. There is a growing trend toward bandwidth-hungry applications driven by data/ video consumption and continuous availability of service. Applications in different areas like in-flight entertainment, maritime connectivity, industrial communications, cellular backhaul via satellite, Internet access to end user,...
We present the design, simulation and measurements of broadband gratings couplers with a variable grating pitch. The measured 3 dB bandwidth was over 110 nm. The gratings employ diamond-shaped sub-wavelength grating (SWG) structures for dispersion control and a varying pitch along the transmission axis.
One of the major challenges in open-ocean deployment of unmanned underwater vehicles (UUVs) or unmanned surface vehicles (USVs) is collision avoidance with approaching surface shipping. Existing methods assume that the underwater robot carries a radar and/or has access via radio to commercial Automatic Identification System (AIS) information. However, radars are expensive and both radars and radio...
A broadband ±45 slant dual-polarized base station antenna element for LTE700/GSM850/GSM900 is presented in this paper. The proposed antenna is composed of two pairs of butterfly radiation patches which are coupling-fed by two Y-shaped microstrip lines. A prototype of the proposed antenna is designed fabricated and test. The measured results show that a bandwidth of 21.7% (0.65–1 GHZ) for VSWR<1...
This presentation overviews recent advances in the designs of low profile circular patch antennas with monopole like radiation patterns. This type of antennas can provide omnidirectional radiation patterns in the azimuth plane. Techniques for the enhancement of the bandwidths are discussed. The antennas can be designed for linear and circular polarizations.
The authors propose the method of building telecommunication systems to transmit information from surveillance cameras in the complex system “Smart house” based on the modified Gold pseudorandom sequences with the length of 15+1 impulses and 4-position PSK signal, which makes possible to reduce the required radio channel bandwidth on the working frequencies in 12.57 times with the given quantity of...
The article measures different aspects of the evolution of the international digital divide between 1986 and 2013. The traditional approach of measuring digital development in terms of telecom subscriptions is increasingly becoming obsolete, especially as mobile phone penetration reaches population saturation levels. It shows that the bandwidth divide continuous to be dynamic and is very persistent,...
This paper presents a characteristic expression to determine the effective bandwidth of broadband wavefields observed over a source-free finite spherical region. To address this topic, for given constraints on size of the observation region and bandwidth, we characterize the observable wavefield using modal expansion of wave propagation in 3D. When signals are transmitted to a spatially constrained...
A broadband two-layered frequency selective surface with miniaturized elements (MEFSS) is presented in this paper. This two-layered MEFSS designed working in X band and Ku band has a low sensitivity to the incident angle and polarization. More important, this two-layered MEFSS has a maximally flat response at low incident angles.
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