An enhancement in the electrical performance of low temperature screen-printed silver nanoparticles (nAg) has been measured at frequencies up to 220 GHz. We show that for frequencies above 80 GHz the electrical losses in coplanar waveguide structures fabricated using nAg at 350 o C are lower than those found in conventional thick film Ag conductors consisting of micron-sized grains and fabricated at 850 o C. The improved electrical performance is attributed to the better packing of the silver nanoparticles resulting in lower surface roughness by a factor of three. We discuss how the use of silver nanoparticles offers new routes to high frequency applications on temperature sensitive conformal substrates and in sub-THz metamaterials.

No abstract

No abstract

Abstract-A novel method is presented for electrically tuning the frequency of a planar inverted-F antenna (PIFA). A tuning circuit, comprising an RF switch and discrete passive components, has been completely integrated into the antenna element, which is thus free of dc wires. The proposed tuning method has been demonstrated with a dual-band PIFA capable of operating in four frequency bands. The antenna covers the GSM850, GSM900, GSM1800, PCS1900 and UMTS frequency ranges with over 40% total efficiency. The impact of the tuning circuit on the antenna's efficiency and radiation pattern have been experimentally studied through comparison with the performance of a reference antenna not incorporating the tuning circuit. The proposed frequency tuning concept can be extended to more complex PIFA structures as well as other types of antennas to give enhanced electrical performance.

No abstract