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Thick film screen-printing technology is employed to introduce planar dielectric antennas. The micron-size-thick film is made from high-permittivity dielectric paste, which is printed on a low-loss low-permittivity microwave substrate to operate as a magnetic wall boundary. A simplified theoretical model is developed to analyze the antenna structure. The accuracy of this model is evaluated by the results of a commercial three-dimensional (3-D) electromagnetic field solver. The model works well with less than 5% deviation from time-consuming simulations, providing the permittivity contrast between the film and substrate is kept high (e.g., > 30). The impact of dielectric loss of the film in antenna performance is significantly less than that of the substrate, allowing medium-loss films (e.g., \boldsymbol\varepsilon^\prime\prime = 3) results in highly efficient antennas with over 95% radiation efficiency. A prototype was made using screen printing and experimentally characterized at Ku-band. The experimental results confirm the theoretical achievements. The measured -10\;\textdB impedance bandwidth of the printable planar dielectric antenna having dimensions of 0.2 \boldsymbol\lambda0 \times 0.2 \boldsymbol\lambda0 is over 10% with a measured gain ranging from 4.5 to 5.5 dBi. Broadside radiation patterns with cross polarization levels of lower than - 20\;\textdB are achieved. This process is compatible with low-temperature cofired ceramic (LTCC) technology where similar idea can be applied to other passive microwave components. [ABSTRACT FROM PUBLISHER]

Planar microwave components are very desirable for many applications and are mainly realized by metallic structures. In this work, a planar dielectric waveguide is proposed. A high-permittivity micrometer-size thick film is patterned on a low-loss microwave substrate and is considered as a nearly perfect magnetic wall to realize the waveguide structure. The permittivity contrast between the film and substrate is kept high (e.g., >\30) in order to minimize the leakage power, and consequently, the insertion loss. The waveguide structure is theoretically analyzed using an approximation method and the results are confirmed by a simulation-based numerical method. The impact of dielectric loss of the film in waveguide performance is much less than that of the substrate, allowing waveguides with films having a medium or high loss (e.g., \varepsilon^\prime\prime = 3) result in a low insertion loss (e.g., up to 0.04 dB/mm at 40 GHz). Several prototypes are fabricated by screen-printing of barium–strontium–titanate (BST) pastes and characterized at 40 GHz. Using the extremely lossy BST film (\tan \delta = 0.2, \varepsilon^\prime\prime = 70), the insertion loss of the waveguide is measured to be 0.18 dB/mm. Based on the current technologies, the printable planar dielectric waveguide can achieve 0.08 dB/mm in insertion loss. Further improvements are expected in the future as the materials and fabrication technologies progress. [ABSTRACT FROM PUBLISHER]