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Dual-polarized antenna is widely used in communication systems such as ECM and DF systems. In this paper a novel double- ridged horn antenna with dual polarizations is introduced for frequency range of 8-18 GHz. Common double ridged horn antennas have single polarization over the operating frequency. We have used five layers polarizer to provide du...
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Two novel MEMS antennas for 60 GHz applications are introduced in this paper. The first antenna is radiating linearly polarized wave, while circularly polarized wave can be radiated from the second antenna. Both antennas possess good isolation from the driving circuit via the presence of ground metal plane. The fabrication process requires only one...
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... Aside from traditional parabolic reflector, 12 synthesizing the surface of the antenna to produce a desired radiation pattern has been considered in the literature. [13][14][15][16] This body-shaping problem is an inverse scattering optimization problem which can be solved by both evolutionary and classic optimization algorithms. However, evolutionary algorithms are more suitable to apply. ...
This article presents a systematic procedure to shape the body of an electrically large object in order to achieve a desired radiation/scattering pattern. In particular, the object surface is described by non‐uniform rational B‐splines (NURBS) and physical optics (PO) is used for electromagnetic field calculations. The NURBS control points and weights are considered as degrees of freedom for an evolutionary optimization algorithm. They are iteratively optimized according to the specific constraints of radiation/scattering problem under consideration. To speedup the optimization process, the electromagnetic codes are implemented on graphics processing unit (GPU). The accuracy of the simulation results are verified by CST commercial electromagnetic software. Furthermore, the results show simulation speedup on the order of several times to a few tens of times. This makes an iterative optimization of a surface rather practical on a single personal computer.
... Since invented in the 1950s, the ridged horn antennas (RHAs) have been drawing attention from worldwide for its ultrawide impedance bandwidth, simple structure, and high power capacity [1][2][3][4]. Hence, the RHAs have been widely used in electromagnetic compatibility testing systems, phased array radars, biology imaging systems, and so on [5][6][7][8][9]. ...
Miniaturization of wideband antennas has attracted much attention for its wide application in modern society. This article proposes a novel broadband miniaturized four-ridged horn antenna (FRHA) with high gain operating from 2.6 to 8.4 GHz. By filling the FRHA with the epoxy-laminated glass cloth board, the side length of the aperture realizes 48% reduction comparing to a traditional ridged horn antenna. The cuboid-shaped polyethylene lens provides good impedance matching between the antenna and the air at low frequencies and decreases the aperture phase error at high frequencies, which optimizes the radiating characteristics in the whole operating band.
... Since the feeder dimensions of the antenna used in the experiments are not available to us, we designed and optimised a DRHA having close return loss (RL or S11) and transmission loss (TL or S21) responses in the frequency range of interest. We will not cover all the details of this design as DRHAs are wellknown and already investigated extensively in the literature [13], [14]. However, the dimensions of the designed antenna, which is presented in Fig. 5, can be found in Table I. with the proposed DRHA is expected to have highly consistent results with the experiments on this spectrum. ...
... The launcher must ensure that the unbalanced coaxial feed is transformed to a balanced double-ridged waveguide geometry, effectively performing the role of a balun, while suppressing higher order modes that could cause pattern deterioration. Various geometries have been used in the past as illustrated in Figure 2. The first designs used a basic empty box cavity ( Figure 2, top left) [2,7,[25][26][27][28]. In most empty box cavities, the ridge is stepped down and extended into the cavity up to the back short. ...
Abstract Broadband double‐ridged guide horn (DRGH) antennas are extensively used in antenna measurement and electromagnetic compatibility and interference testing, especially the 1–18 GHz DRGH antenna which is widely accepted as a standard for this band. Certain deficiencies in the radiation patterns have been identified and corrected by several authors, but the use was still limited to the 1–18 GHz frequency band. The incorporation of absorber materials and lenses has resulted in horn antennas with wider bandwidths; however, this complicates the manufacturing process and restricts these designs to lower power applications. Simulated and measured results for a new 0.5–18 GHz (36:1) DRGH antenna are presented here. The wider bandwidth is made possible by a new cavity design and optimising the design of the other antenna sections to allow wideband operation without using a lens or absorber. The new design has double the bandwidth ratio and is very compact, with an aperture size of 26.4 cm × 15.2 cm; the aperture sides are less than 12% larger than the sides of the aperture of the conventional 1–18 GHz DRGH antenna (24.2 cm × 13.6 cm).
... The realized medium for the antenna had a permittivity of 44.2 at 1 GHz, as provided in Table 2. Hence, the impedance of the medium can be obtained as 56.6 ohms, consequently resulting in a 6.6 times size reduction compared to the case of free-space propagation [34]. This process miniaturized the antenna at the desired frequency. ...
This work presents the thorough hybrid (numerical and experimental) development of a miniaturized microwave antenna, to be better matched to the permittivity of the human skin. This would allow the abdominal fat to be measured more accurately, based on the employed reflection methods with minimal mismatches. This objective was achieved by designing the pyramidal horn antenna that was modeled based on the proposed and manufactured ceramic composite material. Moreover, by using the developed composite of barium titanate and titanium oxide, the ratio of the two could be precisely adjusted, so that the permittivity was a reasonable match to that of the skin. This step was validated by the open-ended probe method. This framework can be instrumental in a range of microwave biomedical applications, which aim to realize the body-centric systems.
... where y is the distance from the waveguide aperture, and L is the axial length to the opening of the exponentially-tapered section, as shown in Fig. 4; k is determined by (3) [30,31]: ...
This paper presents a novel 3D-printed, pyramidal double-ridged horn antenna, filled with a high-dielectric material comprising a mixture of linseed oil and titanium oxide, for biomedical applications. In particular, this investigation explores the use of the antenna design to measure the abdominal fat layers of the human body. The antenna is designed to operate at the low-frequency microwave bands and complemented with an absorber layer at the aperture to improve directivity. The proposed method aims to assess the fat layer thicknesses based on an analysis of the variations of the reflection coefficients. The system has been calibrated and validated based on a number of numerical time-domain simulations, as well as experimental analysis. Assessment of the first transition point in the reflection coefficient spectrum, has successfully predicted the rate of magnitude change caused by different layer thicknesses (e.g., oil and fat). Comparing coefficient spectra from various simulation experiments has allowed for eliminating the interferences arising from mismatches with the skin and muscle layers, resulting in the measurements of the fat layer thicknesses through the remaining power change rate.
... The exponentially-tapered section of the antenna is important as it matches the reference impedance in the feeding point of the device, to that of the material at the aperture that is varying from 50 to 160 ohms, and was obtained by (2) [29] as follows: ...
novel wideband (WB) 3D-printed elliptical double-ridged horn (EDRH) antenna filled with a high-dielectric material (i.e., a mixture of the paraffin and titanium oxide (TiO2)) is proposed for medical monitoring systems. The antenna has been designed and optimized to operate in the frequency range (2–6 GHz) to satisfy an optimal penetration level and to maintain a wideband operation, which results in a high-resolution detection. The proposed antenna is embedded into a high-dielectric material to miniaturize its size and to further reduce the reflections due to mismatch with the body. The antenna was tested on tissue models consisting of two layers (i.e., skin and muscle). The reflection coefficients of the antenna, when it is on the modeled tissue, have been generated and compared with the reference of –6 dB. The obtained results show that the antenna benefits from the 4 GHz of bandwidth with a gain of 5–8 dB within the operating region.
... These conditions include large bandwidth, low side lobes and in the case of separate transmitting and receiving antennas, low cross-coupling levels (Grosvenor et al., 2007). Antennas applicable for impulse radar systems are, for example, spiral (Sato et al., 2005), Vivaldi (Sarkis & Craeye, 2010), bowtie (Congedo et al., 2010), dipole (Qin and Xie, 2016), or transverse electromagnetic (TEM) horn (Mallahzadeh et al., 2008). The TEM horn has been widely used as a very proficient ultra-wideband antenna Qi et al., 2015). ...
In this paper, we set up a lightweight, frequency-domain radar system using a handheld vector network analyser combined with air-coupled and dielectric-coupled horn antennas. A new positioning system with a binary barcode ruler, reading webcam and an algorithm for its recognition was developed. The radar system was tested on several media using both the air-coupled and dielectric-coupled antennas, namely, on a laboratory model containing sand and on a concrete block with a metallic reinforcement. The resulting GPR images demonstrated the good functioning of the radar system. In our experiments, both antennas and the whole lightweight radar system provided radar images which permitted to clearly detect the buried objects. Furthermore, the dielectric-coupled horn antenna showed better coupling with the investigated materials, resulting in higher-quality radar images.
... So, the problem of horn antenna is that its cut-off frequency is limited by the physical size of its aperture. A common solution to lower its cut-off frequency is to insert ridges in the flared part of the antenna [12], [13]. Another solution, which can be even used in combination with the ridges, is to fill in the horn with a dielectric material [14], [15], [16], [17], [18], [19] which reduces the wavelength inside the horn. ...
The aim of this paper is a direct comparison between: 1) a double-ridged horn antenna; 2) the same double-ridged horn filled with sawdust; 3) a bow-tie antenna operating in (approximately) the same band (0.5 GHz 1.5 GHz). The three antennas have been simulated and experimentally tested. The best performances in terms of capability to detect a target behind a 40 cm wall have been obtained with the horn antenna filled with sawdust.
... The bandwidth of DRHAs is extended by placing the tapered ridges in the flared parts of antenna and two ridges in the part of waveguide. Because inserting ridges at upper and lower surfaces of waveguide decreases the lowest cutoff frequency (TE 10 ) and the cutoff frequency of next higher order mode (TE 11 ) increases [4,5]. Therefore it provides that operating frequency range for single mode propagation at the ridged waveguide extends as compared to same dimension of waveguide [6,7]. ...
