A compact planar broadband multiple-input multipleoutput (MIMO) antenna, which has a good performance under MIMO situations with low mutual coupling (<À11 dB) and low correlation coefficient ( À15 dB) is presented. The antenna operates a very wide band with good impedance matching (S 11 <À10 dB), covering the LTE band 33-37 and 39-40. The elements are mounted on the same side of ground plane with the inter-element space of 32 mm. The total size of the array is compact (50 mm  67.2 mm  0.254 mm), suitable for mobile handset applications.

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Electronic packaging evolution involves systems, technology and material considerations. In this paper, we present a liquid crystal polymer (LCP) based multilayer packaging technology that is rapidly emerging as an ideal platform for low cost, multi-band and reconfigurable RF front-end module integration. LCP's very low water absorption (0.04%), low cost and high electrical performance makes it very appealing for RF applications. Here we describe main characteristics and real performance of LCP substrate, by means of several design examples. A Single-Input-SingleOutput (SISO) dual-band filter operating at ISM 2.4-2.5 GHz and UNII 5.15-5.85 GHz frequency bands, a dual polarization, dual frequency 2x1 antenna operating at 14 and 35 GHz, and a WLAN IEEE 802.11a compliant compact module (volume of 75x35x0.2 mm 3 ) have been fabricated on LCP substrate, showing the great potential of the System-OnPackage approach for 3D compact, multi-band and reconfigurable integrated RF and millimeter waves functions and modules. IntroductionMiniaturization, portability, cost and performance have been the driving force for the evolution of packaging and system-on-package (SOP) approach in RF, microwave and millimeter wave applications. Recent research shows SOP to be a more feasible and low cost solution than system-on-chip (SOC) approach [1]. Cost, electrical performance, integration density, and packaging compatibility are variables that are often at odds with each other in RF designs. Few material technologies are able address these considerations simultaneously. LTCC is a technology that has excellent electrical performance, dense multilayer integration, and good barrier properties, but it is relatively expensive compared to standard FR4. Most other substrate and packaging materials do not have low enough water absorption properties in tandem with multilayer construction capabilities to be considered for vertically integrated designs. Liquid crystal polymer (LCP) provides the all-in-one solution for such integration approach in terms of high quality dielectric for high performance multiband passive design, excellent substrate for heterogeneous SOP integration as well as for MEMS structures, enabling the implementation of multiband and reconfigurable modules.In this paper, we present the potential of LCP as the substrate as well as the packaging material for wireless applications. In the following sections, the LCP fabrication

-A novel class of planar reconfigurable directional couplers for intelligent System on Package (SOP) RF front-ends is presented. Reconfigurability is obtained by modifying the electrical parameters of the coupled lines so as to tune the coupling ratio. RF switches such as MEMS or PIN diodes can be used to enable a wide range of reconfigurability in a very compact and low-loss device. The performance and the limitations of the coupler are discussed and design equations are provided. A hardwired prototype in microstrip technology has been manufactured. The novel concept introduced, however, is technology independent so that the reconfigurable coupler can be fabricated in microstrip, stripline or coplanar configurations.