The use of low emissivity windows degrades radio communication. This paper presents design, manufacturing and test measurements for an energy saving window that is transparent to GSM, GPS and 3G radio wave frequencies. A frequency selective structure (FSS) is used in the metallic coating of the window to provide the needed transparency that ranges from 900 MHz to 2 GHz. The periodic pattern used for the FSS is of the aperture type and the elements are hexagon loops. FSS simulations are performed using two different methods, namely the mode matching technique and the Finite-Difference Time Domain method. A frequency selective window is manufactured from a commercially available low emissivity glass. Measurements indicate that the frequency selective window shows an improvement of at least 10 dB in the transmission over the original window.

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Radome diagnostics are acquired in the design process, the delivery control, and in performance verication of repaired and newly developed radomes. A measured near or far eld may indicate deviations, e.g., increased side-lobe levels, but the origin of the aws are not revealed. In this paper, radome diagnostics are performed by visualizing the equivalent surface currents on the 3D-radome body, illuminated from the inside. Three dierent far-eld measurement series at 10 GHz are employed. The measured far eld is related to the equivalent surface currents on the radome surface by using a surface integral representation. In addition, a surface integral equation is employed to ensure that the sources are located inside the radome. Phase shifts, insertion phase delays (IPD), caused by patches of dielectric tape attached to the radome surface, are localized. Specically, patches of various edge sizes (0.5 − 2.0 wavelengths), and with the smallest thickness corresponding to a phase shift of a couple of degrees are imaged.

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