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A 2 × 2 ultra-wideband MIMO flexible antenna with a low profile and good isolation was designed for Internet of Things (IoT) realms and wearable devices. The antenna elements were placed on a novel flexible substrate of liquid crystal polymer (LCP) with compact dimensions fed by a coplanar waveguide (CPW). In order to ameliorate isolation, the cross-shaped decoupling branches were placed among the antenna elements. The proposed UWB antenna can operate from 2.9 GHz to 10.86 GHz with a good reflection coefficient of S11 < −10 dB as well as a high isolation better than 22 dB. Its operating bands include 5G, WiFi, X-band, etc. Moreover, the parameters of diversity performance were also tested. These parameters included an average gain of approximately 4 dB, a low ECC of less than 0.01, and good diversity gain of 9.999. The flexible MIMO antenna performs well in bending and on-body conditions. To sum up, the antenna has good prospects in IoT applications and wearable fields.

Liquid crystal polymer (LCP) has gained wide interest in the electronics industry largely due to its flexibility, stable insulation and dielectric properties and chip integration capabilities. Recently, LCP has also been investigated as a biocompatible substrate for the fabrication of multielectrode arrays. Realizing a fully implantable LCP-based bioelectronic device, however, still necessitates a low form factor packaging solution to protect the electronics in the body. In this work, we investigate two promising encapsulation coatings based on thin-film technology as the main packaging for LCP-based electronics. Specifically, a HfO2–based nanolaminate ceramic (TFE1) deposited via atomic layer deposition (ALD), and a hybrid Parylene C-ALD multilayer stack (TFE2), both with a silicone finish, were investigated and compared to a reference LCP coating. T-peel, water-vapour transmission rate (WVTR) and long-term electrochemical impedance spectrometry (EIS) tests were performed to evaluate adhesion, barrier properties and overall encapsulation performance of the coatings. Both TFE materials showed stable impedance characteristics while submerged in 60 °C saline, with TFE1-silicone lasting more than 16 months under a continuous 14V DC bias (experiment is ongoing). The results presented in this work show that WVTR is not the main factor in determining lifetime, but the adhesion of the coating to the substrate materials plays a key role in maintaining a stable interface and thus longer lifetimes.

This communication presents a novel cactus-shaped ultrawideband (UWB) monopole antenna fabricated on liquid crystal polymer (LCP). The proposed antenna is a very compact design, since it can be fabricated on a board with dimensions only $20\times28$ mm $^{2}$ , while the three linear segments that comprise the cactus-shaped monopole provide a direct control on antenna matching. The proposed antenna is operating from 2.85 to 11.85 GHz and it presents very consistent omnidirectional patterns throughout the UWB frequency range. Return loss and pattern measurements are presented and the operation principles are discussed in detail. The simplicity of this topology, with the easily controllable return loss, allows for its easy implementation for various UWB subband designs, just by building suitable monopole versions, for which the only difference is the length of the three linear segments.

Electronics packaging evolution involves system, technology, and material considerations. In this paper, we present a novel three-dimensional (3-D) integration approach for system-on-package (SOP)-based solutions for wireless communication applications. This concept is proposed for the 3-D integration of RF and millimeter (mm) wave embedded functions in front-end modules by means of stacking substrates using liquid crystal polymer (LCP) multilayer and /spl mu/BGA technologies. Characterization and modeling of high-Q RF inductors using LCP is described. A single-input-single-output (SISO) dual-band filter operating at ISM 2.4-2.5 GHz and UNII 5.15-5.85 GHz frequency bands, two dual-polarization 2/spl times/1 antenna arrays operating at 14 and 35 GHz, and a WLAN IEEE 802.11a-compliant compact module (volume of 75/spl times/35/spl times/0.2 mm/sup 3/) have been fabricated on LCP substrate, showing the great potential of the SOP approach for 3-D-integrated RF and mm wave functions and modules.

Die MID-Technologie erlaubt die Integration mechanischer, fluidischer und elektronischer Funktionen in Spritzgussteilen. Vor allem die Verarbeitung von LCP mittels 2-Komponenten-Spritzguss bietet interessante Perspektiven für MID-Anwendungen.

Die Zwei-Komponenten-Spritzgusstechnik bietet die höchste Gestaltungsfreiheit unter den Herstellungsverfahren für Molded Interconnected Devices (MID). Im Beitrag wird eine Methode zur selektiven Metallisierung von Liquid Crystal Polymer mittels außenstromloser Kupferabscheidung vorgestellt, mit der Zwei-Komponenten-Spritzguss-Bauteile beschichtet werden können. Die Überführung in die Praxis ist jetzt gelungen.

Performance study of wideband tapered step antenna on liquid crystal polymer substrate material is presented. Bandwidth enhancement is achieved by adding step serrated ground on the front side of the model along with the radiating patch. The radiating patch seems to be the intersection of two half circles connected back to back. The lower half circle radius is more than upper half circle radius. Wideband tapered step antenna is designed on the liquid crystal polymer substrate (Ultralam 3850, εr = 2.9) with dimensions of 20×20×0.5 mm. Coplanar waveguide feeding is used in this model with feed line width of 2.6 mm and gap between feed line to ground plane of 0.5 mm.

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-Single-Output (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 2/spl times/1 antenna operating at 14 and 35 GHz, and a WLAN IEEE 802.11a compliant compact module (volume of 75/spl times/35/spl times/0.2 mm/sup 3/) have been fabricated on LCP substrate, showing the great potential of the System-On-Package approach for 3D compact, multi-band and reconfigurable integrated RF and millimeter waves functions and modules.