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A Ku -band low cross-polarization conical horn based on thin metasurface (MTS) walls is presented in this article, along with the relevant design method. The necessary boundary conditions are realized by printing a tensor MTS on the internal walls of the horn, which yields a radiation performance similar to a standard corrugated Gaussian horn yet with the benefits of thin walls. The design method is based on the adiabatic approximate solution for the hybrid mode of a conical waveguide with generic balanced impedance walls, which allows the determination of the impedance profile supporting a single balanced mode. The impedance design is based on the usual locally flat approximation of the wall and on the assumption of plane wave incidence. This approach results in an analytic design method that requires no optimization. The design has been first validated by solving the problem with homogenized impedance boundary conditions through a body of revolution (BoR) method of moments. The actual structure, including impedance wall implementation, is then simulated in full detail with a full-wave fast code. Finally, the horn has been realized and experimentally characterized; measurements show excellent agreement both with theory and with simulations, with a cross-polarization level below −20 dB over a 2 GHz bandwidth. [ABSTRACT FROM AUTHOR]

Gluing an antenna-on-chip (AoC) directly on a ground plane or heat sink in the lead frame is a standard process for commercial applications. To reduce the effect of losses in the silicon substrate and improve the antenna’s radiation efficiency, the wafer thickness is often drastically reduced. However, the close proximity of the antenna and ground plane can cause an impedance mismatch. Metal tiles, which are embedded in silicon dioxide layers, are designed as an artificial magnetic conductor (AMC) to increase the radiation efficiency and tune the antenna impedance. A double-layer AMC is applied instead of a single-layer AMC to reduce the silicon dielectric loss. Additionally, the double-layer AMC has more capacitance to tune the impedance when integrating with a monopole on-chip antenna. The resulting −10 dB impedance bandwidth is increased to 5.8 GHz around the 60 GHz band, the simulated realized gain increases by 3.3 dB, and the simulated antenna radiation efficiency is increased from 11% to 21%. The measured input impedance of the AoC shows good agreement with the simulation results after probe calibration. [ABSTRACT FROM AUTHOR]

The primary objective of many antenna measurement facilities is to provide a specified high accuracy of the measured data. The validation of an antenna measurement facility is the process of proving that such a specified accuracy can be achieved. Since this constitutes a very challenging task, antenna measurement accuracy has been the subject of much research over many years and a range of useful measures have been introduced. Facility comparisons, together with antenna standards, error budgets, facility accreditations, and measurement procedure standards, constitute an effective measure towards facility validations. This paper documents the results of a comparison between 8 European antenna measurement facilities with a specially designed reference antenna, the DTU-ESA 12 GHz Validation Standard Antenna (VAST-12). The electrical and mechanical properties of the VAST-12 antenna are presented and its three different coordinate systems are defined. The primary objective of the comparison is to obtain experience and results that can serve to develop standards for validation of antenna measurement facilities. The paper focuses on the comparison of the radiation pattern and presents not only the measurement data obtained at the facilities, but also investigates several procedures for comparing these data. This includes various definitions of pattern difference and statistical measures as well as a reference pattern. The comparison took place in 2004-2005 as part of the European Union network of excellence called ACE-Antenna Centre of Excellence. [ABSTRACT FROM AUTHOR]