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This paper demonstrates the design, modeling, and analysis of a small size 180 × 165 × 1.6 mm3 printed broadband Vivaldi antenna for electromagnetic compatibility measurements. The proposed antenna is intended to be utilized as a reference antenna for emission and immunity tests inside the EMC Chamber through the band (0.8–5.5 GHz). Exponentially tapered slots were created based on mathematical equations to form an end-fire radiation antenna. Furthermore, microstrip and slot line stubs were employed to tune the impedance bandwidth. This antenna could be considered a 2-D Horn antenna with a size reduction of 64% and 67% since both antennas, Vivaldi and Horn are based on the same principle. Two rectangular slots were engraved near the feeding point to reshape and enhance the gain at lower frequency bands. Furthermore, the realized gain has been improved by approximately 3.5 dB and reached up to 10.7 dBi by introducing a pair of triangular reversal slots at the top edges of the structure. Moreover, this antenna has specifications that make it a suitable candidate to work as a reference antenna inside the EMC chamber compared to the classical Horn antenna offered for sale (PowerLOG® PRO 30800 and TBMA4). [ABSTRACT FROM AUTHOR]

We have developed an affordable horn antenna at St. Stephen's College, which has been used to perform various research-based activities in the college astronomy lab. In this article, we present three of our experiments performed in our undergraduate lab with respect to radio frequency interference in the campus and provide the relevant data. We also present and analyse our results for the 21-cm Hydrogen line emission data collected using our affordable horn antenna. In the third experiment, we study the radiation pattern of our horn antenna. The aim of the article is to present experiments to explore radio astronomy in the lab that can be done by undergraduate students with minimum cost. [ABSTRACT FROM AUTHOR]

A method for generation of ultra-wideband electromagnetic pulses with a nanosecond length and a picosecond rise time has been proposed and studied. A horn antenna with a photoconductive switch irradiated by laser pulses has been used as an emitter. It is shown that the length of ultra-wideband electromagnetic pulses is determined by the antenna length and the semiconductor material and the rise front is determined by the front of laser pulses used to initiate a photoconductive switch. Typical pulse lengths of ~1 ns with a rise front of up to ~34 ps are reported. [ABSTRACT FROM AUTHOR]

In this paper, a tunable polarization converter based on multi-layer metasurface is proposed. It consists of a metal grating, a tunable polarization conversion surface (PCS) and a tunable polarization selective surface (PSS). By changing working states of the PIN diodes embedded on the layers, states of the polarization converter can be switched in real time between co-polarization transmission and cross-polarization conversion. The PSS is not only utilized to construct a Fabry–Perot resonant cavity which helps to achieve polarization conversion, but also can filter out components at undesired polarization to obtain high polarization isolation. To verify the design, a prototype is fabricated and tested. Its overlapping operational bandwidth is 29.3% (2.39–3.21 GHz), and the polarization isolation is higher than 20 dB. In addition, the proposed polarization converter is compatible with the 10-dB standard gain horn antenna. The measured results show that the main lobe of the horn antenna is basically constant within operational band with/without the loading of polarization converter. Meanwhile, the transmittance of the polarization converter is higher than − 3 dB and polarization isolation is higher than 20 dB within 2.49–2.97 GHz. [ABSTRACT FROM AUTHOR]

Probing the Universe with atomic hydrogen 21 cm emission is a fascinating and challenging work in astronomy. Radio telescopes play a vital role in detecting and imaging these faint signals. Powerful radio telescopes are complex to construct and operate. We have built a simple, low-cost 21 cm radio telescope primarily for educational training purposes. The design uses a custom horn antenna, ready-to-use radio-frequency components, and a software-defined radio module. The telescope operates efficiently from a rooftop in a city environment. Using this telescope, we have conducted observations and successfully detected the 21 cm line emissions from the different directions of our galactic plane. Based on the Doppler-shift observed in these measurements, we have successfully derived the Galactic rotation velocity (rotation curve) in those directions. The paper presents the details of the telescope construction, 21 cm observation, and the Galactic rotation curve derivation. [ABSTRACT FROM AUTHOR]

In this paper, a substrate integrated waveguide (SIW) H-plane horn antenna is proposed. We first optimize the antenna in size to obtain the maximum gain. The SIW horn antenna is then corrugated by adding some vias in order to further improve the beam pattern. We use half power beam width (HPBW) as a metric for this improvement. An optimization procedure is also employed to find the best places for the added vias. The horn antenna is implemented on FR4 substrate at 27 GHz frequency band for both with and without corrugation. The results show a good agreement between simulation and measurement. Moreover, it is shown that the SIW corrugated horn antenna reveals a pattern enhancement in terms of HPBW. [ABSTRACT FROM AUTHOR]

This paper reports development, design, and analysis of designer (or spoof) surface plasmon polariton-based feeding configuration to excite a dual-band antenna. As an example, a planar transverse electric and magnetic horn antenna is designed and fed by the proposed transition structure. Designer surface plasmon polariton modes are supported by a metal surface at microwave frequency when it is corrugated with periodical grooves. An efficient transition for converting quasi-transverse electric and magnetic waves of microstrip line into spoof surface plasmon polariton (SSPP) waves has been designed in microwave frequency range using periodically corrugated metal strip. SSPP wave is confined at the teeth part of the corrugation. Simulated and measured reflection and transmission characteristics are in good agreement. The spoof SPP-fed dual-band antenna is designed, fabricated, and characterized in microwave anechoic chamber and measured results are coincident with simulated results. [ABSTRACT FROM AUTHOR]

A real-time imaging system based on a frequency scanning antenna for conveyor belt setups is presented in this paper. The frequency scanning antenna together with an inexpensive parabolic reflector operates at the W band enabling the detection of details with dimensions in the order of 2 mm. In addition, a low level of sidelobes is achieved by optimizing unequal dividers to window the power distribution for sidelobe reduction. Furthermore, the quality of the images is enhanced by the radiation pattern properties. The performance of the system is validated by showing simulation as well as experimental results obtained in real time, proving the feasibility of these kinds of frequency scanning antennas for cost-effective imaging applications. [ABSTRACT FROM AUTHOR]

We present the design, implementation, and characterization of the optics of ALMA Band 1, the lowest frequency band in the most advanced radio astronomical telescope. Band 1 covers the broad frequency range from 35 to 50 GHz, with the goal of minor degradation up to 52 GHz. This is, up to now, the largest fractional bandwidth of all ALMA bands. Since the optics is the first subsystem of any receiver, low noise figure and maximum aperture efficiency are fundamental for best sensitivity. However, a conjunction of several factors (small cryostat apertures, mechanical constraints, and cost limitations) makes extremely challenging to achieve these goals. To overcome these problems, the optics presented here includes two innovative solutions, a compact optimized-profile corrugated horn and a modified Fresnel lens. The horn profile was optimized for optimum performance and easy fabrication by a single-piece manufacturing process in a lathe. In this way, manufacturability is eased when compared with traditional fabrication methods. To minimize the noise contribution of the optics, a one-step zoned lens was designed. Its parameters were carefully optimized to maximize the frequency coverage and reduce losses. The optical assembly reported here fully complies with ALMA specifications. [ABSTRACT FROM AUTHOR]

Continuous-wave (CW) terahertz (THz) imaging with a horn antenna is proposed to enhance the spatial resolution of a THz imaging system. The attached waveguide that is smaller than the wavelength can easily increase the spatial resolution, and the optimized horn flare can significantly increase the transmission power. Consequentially, transmission THz images of a phantom obtained by the amplitude signal using a 0.2 THz wave reveal that the spatial resolution is achieved up to 500 μm. Also, the transmitted power is increased up to 6 times higher compared to the pinhole aperture. The feasibility of CW THz imaging with a horn antenna is demonstrated by the inspection of the organic samples inside food resulting in a relatively high sensitivity for soft organic samples compared with the sensitivity of X-ray imaging to this kind of samples. [ABSTRACT FROM AUTHOR]

We present a design of a high performance horn operating at 700 GHz. The feed, which comprises three smooth-walled conical sections, is easy to machine and yet has comparable performance to a corrugated horn. The measured radiation patterns show high main beam circularity, low sidelobe level and good agreement with theoretical predictions. The cross-polar level is below −20 dB across a frequency bandwidth of 140 GHz. The new design allows the fabrication of high performance, large format feed arrays cheaply and rapidly. [ABSTRACT FROM AUTHOR]

Corrugated horn antennas offer many advantages compared with other waveguide radiators. A major disadvantage which is inherent with the design of a corrugated horn is the fact that slow-wave modes may exist within the horn antenna. In this paper far-field measurements of a W-band horn antenna are presented. The experimental data is compared with simulated data to confirm the presence of slow-wave modes. The analysis is completed by determining the waist, the gaussicity and the phase center location of both the experimental and model data. Finally a redesign approach is proposed which suppresses the slow-wave modes and therefore increases the usable bandwidth of the horn antenna. [ABSTRACT FROM AUTHOR]

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Annals of Telecommunications is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Dans la première partie de cet article, on compare la réponse en fréquence d'un simulateur du type cornet à celle d'un simulateur du type doublet. On utilise les résultats obtenus grâce à un programme de calcul traitant de modèles filaires. Pour des fréquences significatives de la gamme des ondes hectométriques, décamétriques et métriques, on compare les champs rayonnés dans le volume d'essai. Le simulateur du type cornet rayonne de façon plus homogène sur l'ensemble du spectre de fréquence, ce qui est dû à sa forme compacte. Cependant dans un tel simulateur, l'objet à tester peut se trouver couplé avec les structures du simulateur. Ceci peut conduire à des phénomènes d'interaction intolérables. La seconde partie de cet article permet d'apporter des éléments de réponse à cette question. A partir de modèles bidimensionnels, on calcule, à l'aide d'une représentation intégrale, les courants induits sur un objet illuminé par une onde plane. Les résultats obtenus servent de référence pour une comparaison à ceux que l'on obtient lorsque l'objet est illuminé par le simulateur, traité comme une structure de guidage non uniforme. On peut ainsi évaluer l'influence des phénomènes d'interaction sur le temps de montée et l'allure du champ qui excite l'objet. The first part of this paper compares the frequency responses of a horn type and of a dipole type simulators. The field in the test volume is computed using a wire model for the simulators, and its values over a wide frequencies range are compared. The radiation of the horn type simulator is more homogeneous with regard to frequency variations. This is due to the compact shape of this type of simulator. This compactness can lead to a strong and unwanted coupling between the object and the structures of the simulator. In the second part of the paper, the interaction between the simulator and the object is investigated by means of an integral representation of the field, applied to a two dimensional model of the simulator. The latter is considered as a non-uniform guiding structure. The currents on the object along with their rise time and their shape are then used to probe the coupling phenomena. [ABSTRACT FROM AUTHOR]