Design of a continuously tunable reflectarray element for 5G metrology in the k-band

• Main Authors: T. Harz, T. Kleine-Ostmann, T. Schrader
• Format: Article
• Language: deu
• Published: Copernicus Publications 2020-12-01
• Series: Advances in Radio Science
• Online Access: https://ars.copernicus.org/articles/18/1/2020/ars-18-1-2020.pdf

<p>We introduce a new tunable reflectarray element for an operation frequency of 26&thinsp;<span class="inline-formula">GHz</span> in the k-band. It is shown that a 340<span class="inline-formula">^∘</span> continuous tunning range of the reflected wave can be accomplished by using an aperture-coupled patch antenna with only one single varactor diode. The simplified design and the small needed space make it usable for k-band reflectarrays with many elements. The functionality of the reflectarray element is explained and the crucial parts are analyzed. The approach to get a full phase shift is discussed in detail. A bias-T is developed to provide the control voltage to the varactor diode without interfering with the high frequency path. The high frequency path and the DC-path are decoupled by 39&thinsp;<span class="inline-formula">dB</span> using a bias-T. A commercial off-the-shelf varactor diode is selected and its functionality at 26&thinsp;<span class="inline-formula">GHz</span> is verified. Therefore, a test printed circuit board with through, reflect, line standards is developed to de-embed the varactor diode and to evaluate it with a vector network analyzer. The reflectarray is simulated in a unit cell with plane wave excitation and periodic boundary condition using the simulation software package CST Microwave Studio™.</p>