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Polymer–ceramic composites were prepared by twin screw melt extrusion with high-density polyethylene (HDPE) as the matrix and polystyrene-coated BaO–Nd2O3–TiO2 (BNT) ceramics as the filling material. Interestingly, the incorporation of polystyrene (PS) by the coating route could significantly improve the thermal behaviors of the composites (HDPE–PS/BNT), besides the temperature stability of dielectric properties and thermal displacement. The microwave dielectric properties of the composites were investigated systematically. The results indicated that, as the volume fraction of BNT ceramic particles increased from 10 to 50 vol% in the composites, the dielectric constant increased from 3.54 (9.23 GHz) to 13.14 (7.20 GHz), which can be beneficial for the miniaturization of microwave devices; the dielectric loss tangent was relatively low (0.0003– 0.0012); more importantly, the ratio of PS to HDPE increased accordingly, making the composite containing 50 vol% BNT ceramics have a low value of temperature coefficient of resonant frequency ( τf= −11.2 ppm/℃) from −20 to 60 ℃. The GPS microstrip antennas were therefore designed and prepared from the HDPE–PS/BNT composites. They possessed good thermal stability ( τf= 23.6 ppm/℃) over a temperature range of −20 to 60 ℃, promising to meet the requirements of practical antenna applications.


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Thermally stable polymer–ceramic composites for microwave antenna applications

Show Author's information Li ZHANGJie ZHANGZhenxing YUE( )Longtu LI
State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing100084, China

Abstract

Polymer–ceramic composites were prepared by twin screw melt extrusion with high-density polyethylene (HDPE) as the matrix and polystyrene-coated BaO–Nd2O3–TiO2 (BNT) ceramics as the filling material. Interestingly, the incorporation of polystyrene (PS) by the coating route could significantly improve the thermal behaviors of the composites (HDPE–PS/BNT), besides the temperature stability of dielectric properties and thermal displacement. The microwave dielectric properties of the composites were investigated systematically. The results indicated that, as the volume fraction of BNT ceramic particles increased from 10 to 50 vol% in the composites, the dielectric constant increased from 3.54 (9.23 GHz) to 13.14 (7.20 GHz), which can be beneficial for the miniaturization of microwave devices; the dielectric loss tangent was relatively low (0.0003– 0.0012); more importantly, the ratio of PS to HDPE increased accordingly, making the composite containing 50 vol% BNT ceramics have a low value of temperature coefficient of resonant frequency ( τf= −11.2 ppm/℃) from −20 to 60 ℃. The GPS microstrip antennas were therefore designed and prepared from the HDPE–PS/BNT composites. They possessed good thermal stability ( τf= 23.6 ppm/℃) over a temperature range of −20 to 60 ℃, promising to meet the requirements of practical antenna applications.

Keywords:

polymer–ceramic composites, microwave dielectric properties, thermal stability, GPS antenna
Received: 19 May 2016 Revised: 12 July 2016 Accepted: 15 July 2016 Published: 23 December 2016 Issue date: December 2016
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Publication history
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Publication history

Received: 19 May 2016
Revised: 12 July 2016
Accepted: 15 July 2016
Published: 23 December 2016
Issue date: December 2016

Copyright

© The author(s) 2016

Acknowledgements

This work is supported by the National Natural Science Foundation of China (Grant Nos. 51472138 and 51221291), the Ministry of Science and Technology of China through 973 Program under Grant No. 2015CB654605, and Tsinghua National Laboratory for Information Science and Technology (TNList) Cross-discipline Foundation.

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