3D-SOP Millimeter-Wave Functions for High Data Rate Wireless Systems Using LTCC and LCP Technologies

In this paper, the development of three-dimensional (3-D) millimeter-wave functions in multilayer low temperature cofired ceramic (LTCC) and liquid crystal polymer (LCP) technologies is presented for millimeter-wave compact and easy-to-design passive solutions for high data rate wireless systems. Both ceramic and organic technologies are candidates for the 3-D integration of system-on-package (SOP) miniaturized RF/microwave/millimeter-wave systems. LTCC has been widely used as a packaging material because of its process maturity/stability and its relatively high dielectric constant that enables a significant reduction in the module/function dimensions. As an alternative, LCP is an organic material that offers a unique combination of electrical, chemical, and mechanical properties, enabling high-frequency designs due to its ability to act as both the substrate and the package for flexible and conformal multilayer functions. A LTCC patch resonator filter that uses vertical coupling overlap and transverse cuts as design parameters has been designed to achieve a high level of miniaturization and a great compromise between compactness and power handling. Excellent agreement between the simulation and the measurement has been verified for two operating frequency bands (58–60GHz/38–40GHz) of RF communications and sensors for applications such as wireless broadband internet or inter-satellite communications. A band pass filter has been fabricated on LCP substrate, offering a very simple, low loss flexible and low lost filtering solution for wideband millimeter waves applications such as 60 GHz WLAN short-range gigabit wireless systems. The design exploits the ripple near the cut off frequency of Tchebysheff low pass filter to create a band pass response and it exhibits the insertion loss as low as 1.5 dB at the center frequency of 60GHz and 3-dB bandwidth of 16.7% (∼10 GHz).