New three-phase polymer-ceramic composite materials for miniaturized microwave antennas

Li Zhang,Longtu Li,Jie Zhang,Zhenxing Yue

doi:10.1063/1.4964150

Abstract

Unique polymer-ceramic composites for microwave antenna applications were prepared via melt extrusion using high-density polyethylene (HDPE) as the matrix and low-density polyethylene (LDPE) coated BaO–Nd2O3–TiO2 (BNT) ceramic-powders as the filler. By incorporating LDPE into the composites via a coating route, high ceramic-powder volume content (up to 50 vol%) could be achieved. The composites exhibited good microwave dielectric and thermomechanical behaviors. As BNT ceramic content increased from 10 vol% to 50 vol%, the permittivity of the composites increased from 3.45 (9 GHz) to 11.87 (7 GHz), while the dielectric loss remained lower than 0.0016. Microstrip antennas for applications in global positioning systems (GPS) were designed and fabricated from the composites containing 50 vol% BNT ceramics. The results indicate that the composites that have suitable permittivity and low dielectric loss are promising candidates for applications in miniaturized microwave devices, such as antennas.

Highlights

With the rapid development of microwave communication technologies, miniaturization, high performance and low cost have become the main trends in the development of microwave devices, such as circuit substrates, antennas and resonators.[1,2] The ever-increasing demand for microwave antennas requires materials with high permittivity and low dielectric loss to minimize device size and to ensure signal integrity.[3]
The results demonstrate that the new three-phase materials are promising candidates for applications in miniaturized microwave antennas
The results indicate that high-density polyethylene (HDPE) and BNT remain as a heterogeneous mixture, even after the extrusion treatment of the composites

Summary

Introduction

With the rapid development of microwave communication technologies, miniaturization, high performance and low cost have become the main trends in the development of microwave devices, such as circuit substrates, antennas and resonators.[1,2] The ever-increasing demand for microwave antennas requires materials with high permittivity and low dielectric loss to minimize device size and to ensure signal integrity.[3]. Antennas with high permittivity can excite strong surface waves, which inhibit the radiation field and narrow the bandwidth It reduces the transmission efficiency of the antennas, which leads to higher surface loss and lower antenna gain.[4] Because of their low loss, excellent flexibility and ease of processing, polymer materials such as Polytetrafluoroethylene (PTFE) and high-density polyethylene (HDPE) have been widely used in packaging and as substrates for microwave applications. Their low permittivity (

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