Reflectarray Pattern Optimization for Advanced Wireless Communications

A framework for the design and optimization of large dual-linear polarized, shaped-beam reflectarrays for advanced wireless communications is presented. The methodology is based on the generalized intersection approach (IA) algorithm for both phase-only synthesis (POS) and direct optimization of the reflectarray layout, as well as on the use of a method of moments in the spectral domain assuming local periodicity. A thorough description of the design and optimization procedures is provided. To demonstrate the capabilities of the proposed framework, two examples are considered. The first example is a shaped-beam reflectarray for future 5G base stations working in the millimeter waveband, radiating a sectored-beam pattern in azimuth and squared-cosecant pattern in elevation to provide constant power in the coverage area. The second example is a very large contoured-beam reflectarray for direct-to-home (DTH) broadcasting based on real mission requirements with Southern Asia coverage

Dual-Band Integrated Antennas for DVB-T Receivers

An overview on compact Planar Inverted-F Antennas (PIFAs) that are suitable for monitor-equipped devices is presented. In particular, high efficiency PIFAs (without any dielectric layer) with a percentage bandwidth (%BW) greater than 59% (470–862 MHz DVB-T band) are considered. In this context, two PIFA configurations are reviewed, where a dual-band feature has been obtained, in the 3300–3800 MHz (14% percentage bandwidth) WiMAX and 2400–2484 MHz (2.7% percentage bandwidth) WLAN IEEE 802.11b,g frequency bands, respectively, to also guarantee web access to on-demand services. The two PIFAs fill an overall volume of  mm3 and  mm3, respectively. They are composed of a series of branches, properly dimensioned and separated to generate the required resonances. Finally, to show the extreme flexibility of the previous two configurations, a novel dual-band L-shape PIFA has been designed. A reflection coefficient less than −6 dB and −10 dB and an antenna gain of around 2 dBi and 6.3 dBi have been obtained in the 470–862 MHz DVB-T band and the 2400–2484 MHz WLAN band, respectively. The L-shape PIFA prototype can be obtained by properly cutting and folding a single metal sheet, thus resulting in a relatively low-cost and mechanically robust antenna configuration

Davison, Frederick

URSI International Symposium on Electromagnetic Theory (EMTS) (2019. San Diego)This paper presents the state-of-the-art on the synthesis techniques and technologies of the antennas for short-range radio links, when specific focusing/shaping of the radiated field in one or more regions close to the antenna itself (inside the antenna radiative near-field region) is required

General Near Field Synthesis of Reflectarray Antennas for Their Use as Probes in CATR

In this work, reflectarray antennas are proposed for their use as probes in compact antenna test ranges. For that purpose, the quiet zone generated by a single offset reflectarray is enhanced, overcoming the limitation imposed by the amplitude taper of the feed antenna. First, the near field is characterized by a radiation model which computes the near field of the reflectarray as far field contributions of each element, which are modeled as small rectangular apertures and thus taking into account the active element pattern. Then, a phase only synthesis is performed with the Levenberg-Marquardt algorithm in order to improve the size of the generated quiet zone. Due to the nature of the application, this near field synthesis takes into account both the amplitude and phase, making it a more challenging task than an amplitude-only synthesis. The optimization is focused on flattening the amplitude while trying to preserve the phase front generated by the reflectarra