Diagonal Horn Antenna Research Articles

Design of 94GHz Dual-Polarization Antenna Fed by Diagonal Horn for Cloud Radars

In this paper, a 94 GHz dual-polarization high-isolation cassegrain antenna feed by a diagonal horn antenna is designed. The antenna consists of a D = 540 mm main reflector, sub-reflector, and dual-port dual-polarization diagonal horn feed antenna. To obtain similar feed horn E-H radiation patterns, gain, high polarization, and port isolation, a dual-port diagonal horn was designed in the feed. The measured antenna gains are 50.85 dBi and the side-lobe levels are −24.5 dB at E-H radiation patterns of two ports at 94 GHz, respectively. The VSWRs of port 1 and port 2 are less than 1.5:1 in the range 93.2–95.3 GHz, which meets the working requirements of frequency modulated continuous wave and pulse cloud radars. And the isolation between the two ports is above −50 dB, whereas the polarization isolation of each port is above 40 dB. The proposed W-band antenna is a suitable candidate for the dual-polarization cloud radars.

Integration of a field-effect-transistor terahertz detector with a diagonal horn antenna**Project supported by the National Key Research and Development Program of China (Grant Nos. 2016YFF0100501 and 2016YFC0801203), the National Natural Science Foundation of China (Grant Nos. 61611530708, 11403084, 61401456, 61401297, and 61505242), the Six Talent Peaks Project of Jiangsu Province, China (Grant No. XXRJ-079), the Youth Innovation Promotion Association of

Efficient coupling of terahertz electromagnetic wave with the active region in a terahertz detector is required to enhance the optical sensitivity. In this work, we demonstrate direct integration of a field-effect-transistor (FET) terahertz detector chip at the waveguide port of a horn antenna. Although the integration without a proper backshot is rather preliminary, the noise-equivalent power is greatly reduced from 2.7 nW/Hz1/2 for the bare detector chip to 76 pW/Hz1/2 at 340 GHz. The enhancement factor of about 30 is confirmed by simulations revealing the effective increase in the energy flux density seen by the detector. The simulation further confirms the frequency response of the horn antenna and the onchip antennas. A design with the detector chip fully embedded within a waveguide cavity could be made to further enhance the coupling efficiency.

A 740-GHz Dynamic Two-Dimensional Beam-Steering and Forming Antenna Based on Photo-Induced Reconfigurable Fresnel Zone Plates

We report a 0.74-THz beam-steering and forming antenna based on dynamically reconfigurable photo-induced Fresnel zone plates (PI-FZPs) formed by patterned illumination of a high-resistivity silicon wafer using a digital light processing (DLP) projector. This approach eliminates the need for fabrication of circuits or devices on the semiconductor wafer. Using computer-generated PI-FZPs, the beam from a diagonal horn antenna at 740 GHz has been steered from −8 $^{\circ}$ to +8 $^{\circ}$ , consistent with expectations from design and simulations. In addition, the antenna beam width can be dynamically tuned using PI-FZPs with different focal lengths. Both the beam-steering and forming functionalities can be performed simultaneously, enabling applications in THz communications, sensing, and imaging. The PI-FZP antenna performance and design considerations including gain, efficiency, frequency scaling and operation speed are discussed on the basis of the experimental results.

Water‐loaded metal diagonal horn applicator for hyperthermia

This study presents the design of water-loaded metal diagonal horn antenna at 2450 MHz along with simulation and experimental studies of specific absorption rate (SAR) and temperature distributions in a bio-medium (muscle) in direct contact with the water-loaded antenna for hyperthermia application. The metal diagonal horn is a multimode horn antenna, with identical aperture field distribution in the E- and H-planes. The SAR distribution in a phantom muscle in direct contact with water-loaded horn antenna measured at 2450 MHz is nearly in agreement with the corresponding simulated distribution. The simulation results for SAR distribution owing to diagonal horn are also compared with those owing to square aperture horn/box horn, of same aperture cross-section/broader dimension as the diagonal horn at 2450 MHz. The results indicate that the diagonal horn provides higher penetration depth/better transverse resolution over square aperture horn/box horn. In addition, the proposed diagonal horn provides circularly symmetric effective field size. Finally, thermal simulation results are also provided for the proposed applicator, which is in direct contact with a realistic model of muscle medium without and with small spherical as well as oval-shaped tumours of different dielectric properties embedded within the muscle medium.

Characterization of terahertz antennas using photoinduced coded‐aperture imaging

ABSTRACTWe report a novel approach for characterization of terahertz (THz) antennas using the photoinduced coded‐aperture imaging (PI‐CAI) technique. For a prototype demonstration, a WR‐1.5 (500–750 GHz) diagonal horn antenna has been fully characterized. The THz beam radiated from the antenna was imaged using the PI‐CAI technique at different distances from the antenna aperture. The measured beam profiles show near‐Gaussian shapes, with the expected propagation properties. The far‐field antenna radiation patterns were then extracted from the far‐field beam image and compared with conventional measurement results, theoretical calculation and full‐wave simulation. Finally, the antenna Gaussian coupling efficiency was calculated to be ∼83% based on the two‐dimensional (2‐D) beam mapping technique. Antenna radiation parameters obtained using the above approach show good agreement with published literature and manufacturer datasheets, demonstrating the potential of the PI‐CAI approach for fast and accurate characterization of THz antennas. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1180–1184, 2015

THEORETICAL AND SIMULATION STUDIES ON WATER-LOADED METAL DIAGONAL HORN ANTENNA FOR HYPERTHERMIA APPLICATION

This paper is a continuation of our previous published work in which a water-loaded metal diagonal horn antenna has been designed at 2450 MHz for hyperthermia application and simulated results are compared with those measured. In the present study, theoretical investigations of Specific Absorption Rate (SAR) distribution in a homogeneous biological phantom (muscle) due to direct contact water-loaded metal diagonal horn antenna at 915 and 2450 MHz for hyperthermia application is presented. It is estimated theoretically that, at both the operating frequencies, a reasonable impedance matching is achieved at the interface between the antenna aperture and the biological phantom, where a computation of aperture admittance and reflection coefficient has been performed. Furthermore, it is confirmed through theoretical and simulation studies that the proposed horn antenna gives circularly symmetric SAR distribution in transverse plane in the biological phantom at 915 and 2450 MHz. The simulated and theoretical SAR distributions at 2450 MHz are compared with those determined at 915 MHz. In addition, thermal simulation results based on Pennes' Bio-heat equation (BHE) are applied to the realistic muscle model at 915 and 2450 MHz. The reduction of blood flow rate on temperature distribution is also studied.

A 1.485-Gbit/s Video Signal Transmission System at Carrier Frequencies of 240 GHz and 300 GHz

A 1.485-Gbit/s video signal transmission system at carrier frequencies of 240 GHz and 300 GHz was implemented and demonstrated. The radio frequency front-ends are composed of Schottky barrier diode subharmonic mixers (SHMs), frequency triplers, and diagonal horn antennas for the transmitter and receiver. Amplitude shift keying with an intermediate frequency of 5.94 GHz was utilized as the modulation scheme. A 1.485-Gbit/s video signal with a high-definition serial digital interface format was successfully transmitted over a wireless link distance of 4.2 m and displayed on an HDTV with a transmitted average output power of 20 µW at a 300-GHz system.

H-대역(220~325 GHz) 주파수를 이용한 1.485 Gbps 비디오 신호 전송 송수신기

H-대역(220~325 GHz)의 주파수 범위에서 동작하는 송신기와 수신기를 구현하였으며, 1.485 Gbps 비디오 신호 전송을 국내 최초로 시연하였다. H-대역의 RF front-end는 쇼트키 배리어 다이오드 기술을 이용한 서브 하모닉 믹서, 주파수 3배기, 대각선 혼 안테나로 구성하였다. 송신 및 수신 캐리어 주파수는 H-대역 중에서 246 GHz를 사용하여 구현하였고, 서브 하모닉 믹서의 LO 주파수는 각각 120 GHz, 126 GHz이다. 변조 방식은 ASK(Amplitude Shift Keying), IF 주파수는 5.94 GHz이며, 수신기는 헤테로다인 구조와 ZBD(Zero Bias Detector) 두 방식 모두를 이용하여 envelop 신호를 검출하는 방식이다. HD-SDI 형식을 갖는 1.485 Gbps 비디오 신호를 송신기 출력 20 <TEX>${\mu}W$</TEX>에서 약 5 m까지 성공적으로 HDTV로 전송하였다. An 1.485 Gbit/s video signal transmission system using the carrier frequency of H-band(220~325 GHz) was implemented and demonstrated for the first in domestic. The RF front-end was composed of Schottky barrier diode sub-harmonic mixers(SHM) and frequency triplers, and diagonal horn antennas for transmitter and receiver, respectively. The transmitted carrier frequency of 246 GHz was implemented in the H-band, and LO frequencies of H-band SHM is 120 GHz and 126 GHz for transmit and receive chains, respectively. The modulation scheme is ASK(Amplitude Shift Keying) where IF frequency is 5.94 GHz and the envelop detection was used in heterodyne receiver architecture, and direct detection receiver using ZBD(Zero Bias Detector) was implemented as well. The 1.485 Gbit/s video signal with HD-SDI format was successfully transmitted over wireless link distance of 5 m and displayed on HDTV at the transmitted average output power of 20 <TEX>${\mu}W$</TEX>.

Radiation pattern and properties of double-flared diagonal horn antenna

This article is concerned with analytical model for radiation pattern of a new double-flared diagonal horn antenna using “plane wave spectra technique for 3D fields”. The double-flared diagonal horn antenna is accomplished by adding one more set of flares in E- and H-planes with equal flare angles into conventional diagonal horn. The copolarized and cross-polarized radiation patterns in E-, H-, and D-planes have been computed utilizing the analytical model and reported in the article. The parametric studies on peak cross-polarization level have carried out. The radiation performance of double-flared and conventional diagonal horns for same length and aperture size are also compared. It is investigated that double-flared diagonal horn antenna posses better peak cross-polarization level (≈−16.5 dB) in D-plane (±45° plane) in comparison of conventional diagonal horn (≈−15.5 dB) at design frequency and retains almost circularly symmetric radiating beam at lower values of elevation angles. Also, double-flared diagonal horn has better matches with free-space and has slightly lower gain (≤0.5 dB) in comparison of conventional diagonal horn. The work presented here can provide useful design guidelines for development of prototypes of double-flared diagonal horn, which may find potential application in satellite communication and imaging applications etc. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.

Near Field Distribution of Hollow Dielectric Wall Diagonal Horn Antennas

Aperture/near-field distributions of hollow dielectric wall diagonal horn antennas have been studied theoretically and experimentally. Solutions of the Helmholtz equation are obtained for TE to x and TE to y modes using separation of variables technique for the horn assumed to be made of an equivalent homogeneous dielectric material of dielectric constant equal to the effective dielectric constant of dielectric slabs and inner free space region bounded by these slabs. Transcendental equations for the transverse components of propagation constants are obtained by applying proper boundary conditions, i.e. the continuity of the electric and magnetic fields at the interfaces each between the dielectric region and outer free space region. These transcendental equations are solved for the transverse propagation constants for the fundamental mode for five horns each of axial length = 12.8 cm and flare angle = 8.5° at 9.418 GHz in the x-band. The dielectric constant of the dielectric slabs used in fabricating the five horns are equal to 2.54, 2.56, 2.56, 2.80 and 3.03 and respective slab thicknesses are equal to 0.15, 0.15, 0.32, 0.32 and 0.32 cm. The theoretical aperture-field distributions obtained for Hx11, and Hy11modes propagating in these antennas are compared with corresponding experimental ones.

Near field distribution of solid dielectric diagonal horn antennas

Aperture/near field distributions of solid dielectric diagonal horn antennas have been studied, both theoretically and experimentally. Solution of the Helmholtz equation is obtained for TE to x and TE to y modes using separation of variables technique for the horn. Transcendental equations for the transverse components of the propagation constants are obtained by applying proper boundary conditions, i.e. the continuity of the electric and magnetic fields at the dielectric-air boundaries. These transcendental equations are solved for the transverse propagation constants for the fundamental mode for three horns each 1 of axial length = 12.8 cm and flare angle = 8.5° and with dielectric constants ε 1 of the materials of the horns equal to 2.54, 2.56 and 2.80 at the frequency 9.418 GHz in the-band X-band. The theoretical aperture field distributions obtained for Hx 11 and Hy 11 modes propagating in these antennas are compared with corresponding

Far field patterns of solid dielectric diagonal horn antennas

Far field patterns of solid dielectric diagonal horn antennas of various dielectric constants (ε 1 = 2.54, 2.56 and 2.80) are studied theoretically and experimentally at 9.418 GHz. Theoretical near field distributions at the aperture and at the four side surfaces of a horn under study for TE x to and TE y to modes are obtained by solving Helmholtz's equation using the separation of variables technique. The expressions for the near field components of the horn under study are used to obtain the expression for radiation pattern from Kirchoff's diffraction formula. The theoretical far field patterns obtained for these antennas are compared with the corresponding experimental ones.

Diagonal horn integrated with micromachined waveguidefor submillimetreapplications

The feasibility of coupling silicon micromachines rectangular waveguide to a modified diagonal horn antenna using a model at 110 GHz is demonstrated. The antenna patterns obtained are similar to those obtained with a standard diagonal horn. A method of reducing the on-axis cross polarization response of diagonal horns is also presented.

Radiation patterns of metal and dielectric wall diagonal horn antennas

The radiation patterns and gain of dielectric wall diagonal horn antennas of various thicknesses (0.15cm and 0.32 cm) and dielectric constants (ϵ = 2.54, 2.56 and 3.03) have been experimentally studied and compared with a metal diagonal horn antenna having the same aperture at 9.418 GHz. Radiation patterns of these dielectric horn antennas when used as square horns are also presented and compared with a similar metal horn. The use and applicability of dielectric horn antennas is discussed.

High-gain step-profiled integrated diagonal horn-antennas

Dipole-excited integrated horn antennas are limited by their large flare angle of 70 degrees , which is inherent in the anisotropic etching process of

Circularly Polarized Antenna for Transmitting Application

Broadband Circularly Polarized Diagonal Horn Antennas, capable of high power handling working over frequency 2.4 GHz through 12.4 GHz have been designed and developed. Low loss, high strength radome has been used to protect the antennas. The diagonal horn possesses almost perfect circular symmetry beam; thus resulting in low axial ratio off the antenna axis also. This antenna has very low side lobe in principal planes compared to conventional pyramidal horn of square cross section.The antenna is having directional coverage and can be used for high power transmitting application. Experimental results are presented. This type of antenna is ideally suited for shipborne, vehicle mounted and airborne applications.