Vers la longueur d'onde de la bande E : Corne ondulée gaussienne imprimée en 3D pour l'application d'antenne Cassegrain

Two Gaussian profile conical horn antennas for use within the E-band spectrum are presented. The proposed conical horn antenna is designed in three segments: Mode converter, phasing and profiled sections. These two horns with Cos n-like radiation patterns as Cassegrain antenna illuminators are analyzed to have high efficiency over the E-band (60-100GHz). Simulations show reasonable results, therefore allowing for reliable predictability. A couple of printing technologies and metal materials to realize proposed designs are analyzed with material characterizations throughout simulations, namely selective laser melting (SLM) using Cu-15Sn material and binder sintering on 316L stainless with 2.79 µm, 12.79 µm surface roughness, respectively. The slot-to-ridge width ratio for both designs is fixed to 4:1 ratio, with a pitch of λ/4 at 100 GHz. The provided horn antennas' impedance bandwidth (|S11| < −24 dB) covers the whole intended operational band for both E-and D spectrum. The realized in-band gain for the E-band antennas is higher than 22.14 and 22, respectively

Human Body Specific Absorption Rate Reduction Employing a Compact Magneto-Dielectric AMC Structure for 5G Massive-MIMO Applications

A compact artificial magnetic conductor (AMC) structure for the application of specific absorption rate (SAR) reduction is presented in this paper. A magneto-dielectric (MD) structure as a host of AMC substrate is used to miniaturize the AMC size. The magneto-dielectric has been designed with a low-profile spiral loop in a way to have a high permittivity and permeability for the desired center frequency of 3.5 GHz. Simulation results confirm the zero-degree reflection phase of the proposed AMC unit cell. Moreover, a 70% reduction has been achieved in comparison to the conventional AMC. To validate the simulation results, a prototype of the board is fabricated and measured with a coplanar waveguide (CPW) antenna for the reflection coefficient. The measurement results display an excellent agreement with the simulation ones. A VOXEL model of a human body is utilized to determine the SAR value of the proposed structure. Considering the maximum SAR value for an average of 10 g human tissue, more than 70% SAR reduction is verified for the CPW antenna with the recommended MD-AMC structure compared to a conventional single CPW antenna

A Novel Planar Power Divider/Combiner for Wideband High-Power Applications

This manuscript presents a novel wideband power divider with high power handling capability. The power handling capacity of the power divider is increased through the use of grounded 50 ohm loads. The full circuit analysis of a single section of the proposed structure is presented utilizing even and odd modes and ABCD matrices. The final designed sections are cascaded and extended to achieve a high bandwidth response for the target of X-band. The structure was designed and optimized with the method of moments based on ADS software and simulated in HFSS for 3D full-wave analysis. A prototype module was fabricated and measured for experimental validation. The simulation results were confirmed by through measurements for the frequency band of 7–12 GHz (more than 52% fractional bandwidth). A divider such as the proposed one has a significantly higher power handling capacity than Wilkinson, as well as a wider frequency bandwidth than Gysel power dividers. As a wideband high-power power divider, the proposed device is ideal for high-data rate radar or satellite applications

Nonreciprocal-beam phased-array antennas based on transistor-loaded phase shifters

This study presents a nonreciprocal-beam phased-array antenna constituted of phase-gradient patch radiators integrated with transistor-based nonreciprocal phase shifters. Such an antenna exhibits different beams for transmission and reception states. The proposed phased-array antenna provides power amplification for both transmission and reception states, which is of paramount importance in most practical applications. In addition, in contrast to the recently proposed time-modulated antennas, the proposed nonreciprocal-beam phased-array antenna introduces no undesired time harmonics and unwanted frequency conversion, which requires no radio frequency bias signal. Furthermore, the nonreciprocal phased-array antenna is lightweight and is amenable to integrated circuit fabrication. The transmission and reception beam angles, the beam shapes, and the power amplification level may be easily tuned by changing the direct current (dc) bias of the transistors and phase of the passive phase shifters. Such a nonreciprocal-beam phased-array antenna is expected to find military and commercial applications. </p