Dual-polarized Horn Antenna Research Articles

A high-performance compact WR-4 orthomode transducer for wideband communications

Abstract This paper presents the design, fabrication and performance evaluation of a compact orthomode transducer (OMT) optimized for wideband communications. The OMT developed in this work features a circular waveguide as its common port, ensuring direct compatibility with receivers such as horn antennas, meanwhile enabling dual-polarization capabilities. The operational frequency spectrum of the OMT spans the entire WR-4 band (170 GHz-260 GHz), achieving reflection coefficients surpassing 20 dB and port isolation better than 60 dB, as validated through electromagnetic (EM) simulations. To evaluate performance of the fabricated OMT in a practical dual-polarization system, the OMT is utilized as the feed source for a horn antenna to realize a dual-polarized horn antenna system. The results demonstrate that the antenna incorporating the OMT exhibits superior performance, with average reflection coefficients better than 20 dB and port isolation exceeding 40 dB for overall operational band. These results indicate that the OMT developed in this work successfully meets the demanding requirements for polarization multiplexing in wideband dual-polarized receiver systems.

A Novel Wideband Tightly Coupled Dual-Polarized Reflectarray Antenna

In this communication, a novel tightly coupled dual-polarized reflectarray antenna is presented. The antenna consists of a dual-polarized feed antenna and a wideband dual-polarized reflecting surface. The reflecting surface is composed of dual-polarized tightly coupled unit cells. Each unit cell contains two types of elements, of which the polarizations are perpendicular. Each element contains a dipole and a delay line. For one polarization, the reflecting surface consists of 13 × 34 elements, while there are 26 × 11 elements on the reflecting surface for the other polarization. The feed antenna is a wideband dual-polarized horn antenna. The phase error distribution on the reflecting surface is analyzed as well. To verify the design, a prototypical tightly coupled dual-polarized reflectarray antenna operating from 3 to 8 GHz is simulated, manufactured, and measured. The simulated results are in good agreement with the measured results. In the working band, the radiation patterns of the proposed reflectarray antenna are stable.

Design of the cross-polarization scattering diagnostic on the HL-2A tokamak

A new cross-polarization scattering (CPS) diagnostic has been developed on HL-2A, which aims to measure the local magnetic fluctuation inside the plasma. It is based on the scattering of an incident microwave beam into the perpendicular polarization by magnetic fluctuations. The CPS diagnostic has been designed in the Q-band (33–50 GHz), which consists of the electronic system, quasi-optical, and polarization rejector. The ray-tracing code is used to simulate the propagation of the probe and scattered rays. To test the performance of the quasi-optical system, a 3D test platform is built and detailed test results are shown. Two methods are developed for polarization rejector on HL-2A: wire grid polarizer and dual-polarized horn antenna (DPHA). The laboratory test result shows that the polarization rejection of both methods is better than 30 dB, which meets the needs for magnetic fluctuation detection. In the future, the CPS diagnosis will be used to study the electromagnetic turbulence behavior in the high-performance plasma of the HL-2A tokamak.

W-band frequency-polarization-port-diverse cavity imager with bunching random beams

A frequency-polarization-port-diverse (FPPD) cavity imager with bunching random beams working in the W-band (from 76 GHz to 81 GHz) is proposed in this paper. A random-coherent-superposition design method is utilized to design the bunching random beam. Low-correlated radiation patterns can be generated when excited either at different frequencies or by different ports. Orthogonal polarized radiation patterns also vary from each other, which can enlarge measurement modes from the polarization dimension. The FPPD cavity imager is composed of a disordered cavity, a lid etched with elliptical holes and a dual-polarized horn antenna. Frequency-port-diverse electric field distributions of the disordered cavity are achieved by loading irregular structures and FPPD radiation patterns are realized by etching elliptical holes with various minor axis lengths and rotation angels. A dual-polarized horn antenna is used to generate the bunching radiation patterns, on which we superpose the random radiation patterns. Definitions of the bunching angle and the correlation coefficient are also given to evaluate the performance of the FPPD cavity imager. Finally, a coincidence imaging experiment is used to investigate the FPPD cavity imager under different conditions and the target image has been reconstructed successfully. Advantages of the bunching characteristic are also proved by comparative experiments using the bunching radiation patterns and the normal radiation patterns. High-quality reconstruction of the target image demonstrates the feasibility of the multi-dimension joint (i.e. frequency, polarization and port) design method. The proposed method is verified by simulations and measurements.

<inline-formula> <tex-math notation="LaTeX">$E$ </tex-math> </inline-formula>-Band Substrate Integrated Waveguide Orthomode Transducer Integrated With Dual-Polarized Horn Antenna

This paper presents an E-band substrate integrated waveguide (SIW) dual-polarized antenna system, which consists of an orthomode transducer (OMT) and a dual-polarized horn antenna. On the basis of a two-layer substrate design, the function of OMT is realized by utilizing an SIW section to excite TE10 mode for the vertical polarization, a quasi-coaxial stripline to excite quasi-TEM mode for the horizontal polarization. And also, a slot line transition is placed at the common port of the two structures for impedance matching with the ridge SIW dual-polarized horn antenna. In this way, the dual-polarized horn antenna is designed with an exponential ridge structure simultaneously for better impedance matching and higher efficiency of the antenna. To verify the functionality of the proposed integrated OMT-antenna structure, an experimental prototype is fabricated and measured, and a good agreement is found between its simulation and measured results. Over the frequency range of 83–87 GHz, return loss better than 10 dB at all ports and cross-polarization less than −25 dB are obtained. The maximum antenna gain is about 14 dBi for the horizontal polarization and 15.2 dBi for the vertical polarization. It is believed that the proposed OMT-antenna design is suitable for ultrahigh capacity millimeter-wave backhaul applications in future wireless communication systems.

A Polarimetric Active Transponder With Extremely Large RCS for Absolute Radiometric Calibration of SMAP Radar

This paper presents a new single-antenna polarimetric active radar calibrator (PARC) intended for the polarimetric and absolute radiometric calibration of the NASA’s soil moisture active passive (SMAP) radar. The PARC receives and retransmits the SMAP signal through a dual-polarized horn antenna with 17-dB gain at the center frequency of 1.26 GHz with 100 MHz of bandwidth. The transmit and receive polarizations are perpendicular and are isolated from each other using a precision orthomode transducer (OMT) specially designed for this application. The antenna is rotated 45° in the plane perpendicular to the direction of incidence, so that the scattering matrix of the PARC with respect to SMAP polarization coordinates has equal entries that enable radiometric calibration of all four channels simultaneously. As SMAP radar resolution is coarse (1 km), a point target with a very large radar cross section (RCS) is required to provide a high signal-to-clutter ratio. The proposed PARC can provide RCS values as high as 80 dBsm to achieve a 30-dB signal-to-clutter ratio. The PARC is controlled by a microcontroller to autonomously start minutes before the SMAP radar is expected to scan the area, stabilize the amplifier gain, record the magnitude of the pulses transmitted from the radar, and transmit these data to a base station. The design procedures of the OMT and the antenna, as well as control and RF circuits, are discussed, a number of leakage cancelation techniques are introduced to increase the isolation between the ports, the RCS of the fabricated PARC is fully characterized, and the image of the PARC as seen by SMAP is presented.

Measured 21.5 GHz Indoor Channels With User-Held Handset Antenna Array

For mobile systems involving hand-held devices, the influence of the user on system performance has to be considered. Extensive studies below 6 GHz have demonstrated large effects on system performance. However, the impact of user influence at potential frequency bands for upcoming 5G mobile networks is still to be investigated. This paper investigates how the user affects the performance of a 5G handset mock-up. The user impact is studied by channel sounding in an indoor scenario, with and without the presence of different users. The mock-up handset has a uniform linear array of receive (Rx) antennas operated at 21.5 GHz. A dual-polarized horn antenna with a wide beamwidth is transmit antenna and a fast channel sounder is used, allowing for dynamic and realistic channels. The results show that the mean influence of the user on the power varies considerably depending on the scenario, with more than 12 dB loss in some cases, while a gain of 4 dB is seen in other. An important finding is that the mean power among the seven Rx branches may be very different. Branch power ratios in the typical range of 2–10 dB were found, depending on the user and scenario.

Orthomode Transducer and Dual-Polarized Horn Antenna in Substrate Integrated Technology

A dual-polarized system fully implemented in substrate integrated technology is presented. It comprises an orthomode transducer (OMT) with planar excitation schemes for both orthogonal TE10- and TE01-modes and a dual-polarized horn antenna. The whole structure requires only two layers of substrate, and it is based on the extended substrate integrated waveguide (ESIW), which allows the propagation of TEm0- and TE0n-modes. A compact OMT design is proposed along with a procedure to optimize it. The matching and radiation characteristics of a dual-polarized horn antenna fed with this OMT are also studied. The complete structure was manufactured exhibiting an 8.6% bandwidth (13.9-15.15 GHz) where both modes are well matched ( 28 dB). The horn radiation patterns within the frequency range of operation are also similar for both polarizations. The proposed design demonstrates the feasibility of dual-polarized substrate integrated circuits (SICs). This opens the door to new substrate integrated devices as well as to the use of SICs in applications requiring polarization diversity at end-fire. All together, this combined design becomes a promising approach to tackle the increasing demand for capacity in modern communication systems.

A NEW DUAL-POLARIZED HORN ANTENNA EXCITED BY A GAP-FED SQUARE PATCH

A new dual-polarized horn antenna fed by a microstrip patch is proposed. The patch is excited in two orthogonal polarizations by small gaps between the patch edge and the microstrip open end. A horn antenna operating at 14.9GHz is designed, fabricated and tested. Measurements show that the horn has a re∞ection coe-cient of less than i10dB, and a port isolation greater than 30dB, over 14.6{ 15.2GHz, and a gain of 12.34dBi and 10-dB beamwidths of 87 - and 88 - at 14.9GHz.

Millimeter-Wave Dual Polarized L-Shaped Horn Antenna for Wide-Angle Phased Arrays

A new broadband dual polarized L-shaped horn antenna and associated waveguide feed structure is presented. The antenna is well suited for millimeter-wave polarimetric phased array systems requiring wide-angle scanning and ease of integration with planar circuits. A stereolithographic fabrication process is employed to obtain the complex angles and intricate features that are essential for the antenna and feed design. Dielectric material is used to fill the horn antenna and waveguide feed, which allows for the desired radiation characteristics as well as low loss transition to the microstrip circuitry. Broadband attributes are demonstrated with measured return losses of better than -10 dB from 34 to 40 GHz. The measured gain is 5.3 dB at 35 GHz, along with 19 dB cross-polarization discrimination