Future commercial and military communication systems require a new class of antennas and radio frequency (RF) front-ends that are small, light-weight, conformal, and multi-functional. This dissertation is dedicated to the development and application of the novel polymer-ceramic composites for future compact multilayer antennas and RF systems. The first half of the dissertation deals with the fabrication and characterization of the polymer-ceramic composites. Also, carbon nanotube (CNT) sheets are introduced for the first time to overcome the issues of reliable printing on polymers. The second half of the dissertation focuses on the application of the polymer-ceramic composites with carbon nanotube sheet printing. Two practical application examples are elaborated, namely (1) a compact anti-jamming GPS array and (2) a cylindrically conformal microstrip array. Both applications demonstrate the potentials of the polymer-ceramic composites for three-dimensional fabrication and multilayer packaging.