Low temperature co-fired ceramic antenna for 35 GHz applications with a wideband GCPW to stripline transition

In this paper we present the design, electromagnetic simulation and experimental results of a 35 GHz Low Temperature Co-Fired Ceramics (LTCC) antenna and a LTCC grounded coplanar waveguide (GCPW) to stripline (SL) transition. The stripline-fed antenna and the GCPW-to-SL transition are designed for a six-tape LTCC process. For characterization purposes, two back-to-back transitions are fabricated and measured, showing reflection losses lower than -10 dB between 27-46.7 GHz, and insertion losses lower than 1.5 dB in this frequency range. The insertion losses of the back-to-back transition are remarkably low in the whole Ka band (26.5-40 GHz), with estimated losses between 0.15-0.5 dB for a single transition. The antenna element has four parasitic microstrip patches and a simulated directivity of 8.2 dBi at 35 GHz. The antenna element integrated with the transition is fabricated and characterized on wafer. The integrated structure shows measured reflection losses lower than -10 dB between 34.48-36.39 GHz. The transmission characteristic as a function of frequency is recorded and in good agreement with the simulated gain. The overall size of the fabricated antenna with transition is 6:24 * 8:975 mm2, with the standalone antenna element having a size of just 6:24*6:15 mm2.