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Phase Agility of Reflectarray Patch Element Using Nematic Liquid Crystal

M. Yusof Ismail, (2007) Phase Agility of Reflectarray Patch Element Using Nematic Liquid Crystal. Jurnal Teknologi, 47 (D). pp. 131-138.

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Affiliations

Queen’s University of Belfast. The Institute of Electronics, Communications and Information Technology

Abstract

Abstract: There has been much interest recently in developing reconfigurable reflectarray antenna for tunable microwave applications. Liquid crystal (LC) has been given much attention due to its dielectric anisotropy property which allows the change in the frequency and hence the reflection phase. In this paper, the phase agility of the periodic array using K15 nematic liquid crystal as the dielectric permittivity is presented. Numerical and experimental results at X–band are used to compare the plane wave scattering parameter from a two patch reflectarray cell of 500 μm. A tunable dynamic phase range of 221° is achieved over a broad band of 170 MHz which also gives a tunability of 0.39.

Abstrak: Terdapat kajian yang cukup meluas darsa warsa ini dalam membangunkan teknologi antenna tatasusun terpantul yang boleh dimanfaatkan dalam kepelbagaian aplikasi kebolehtukaran gelombang mikro. Laporan kajian terkini menunjukkan bahawa kristal cecair telah diberikan tumpuan yang memberangsangkan oleh para pengkaji memandangkan ciri kebolehubahan dielektriknya yang membenarkan perubahan dalam frekuensi dan seterusnya fasa pantulan antena. Dalam kertas kerja ini, kebolehtukaran fasa untuk tatasusun antenna menggunakan bahan kristal cecair dalam fasa nematik K15 sebagai bahan dielektrik dibentangkan. Pengukuran bagi parameter taburan telah dijalankan menggunakan teknik simulator pandu gelombang dengan aplikasi voltan dc daripada 0 hingga 20 V. Keputusan–keputusan simulasi dan eksperimen dalam julat jalur frekuensi X digunakan untuk membandingkan parameter taburan gelombang sekata daripada sel tatasusun antena berkristal cecair yang berketinggian 500 μm. Keputusan eksperimen menunjukkan bahawa julat fasa dinamik setinggi 221° telah dicapai menerusi julat frekuensi berjalur lebar 170 MHz yang turut memberikan nilai kebolehtukaran sebanyak 0.39.

Item Type:Journal
Additional Information:M. Yusof Ismail is supported by a scholarship from the University of Tun Hussein Onn Malaysia
Keywords:Dielectric anisotropy, liquid crystal, phase range, tunability, Kebolehubahan dielektrik, kristal cecair, julat fasa, kebolehtukaran
Subjects:T Technology, Engineering
ID Code:4037

[1] Pozar, D. M. and T. A. Metzler. 1993. Analysis of a Reflectarray Antenna Using Microstrip Patches of Variable Size. Electron. Lett. 29(8): 657-658.

[2] Pozar, D. M. 1999. A Shaped-beam Microstrip Patch Reflectarray. IEEE Trans. Antennas Propag. 47(7):1167-1173.

[3] Menzel, W., D. Pilz, M. Al-Tikriti. 2002. Milimeter-wave Folded Reflector Antennas with High Gain, Low Loss and Low Profile. IEEE Antennas and Propagation Magazine. 44(3): 24-29.

[4] Hum, S. V., M. Okoniewski, and R. J. Davies. 2005. Realizing an Electronically Tunable Reflectarray Using Varactor Diode-tuned Elements IEEE Microwave and Wireless Components Letters. 15(6): 422-424.

[5] Martin, N., P. Laurent, C. Person, P. Gellin, and F. Huret. 2003. Patch Antenna Adjustable in Frequency Using Liquid Crystal. 33rd European Microwave Conference. Munich. 699-701.

[6] Dolfi, D., M. Labeyrie, P. Joffre, and J. P. Huignard. 1993. Liquid Crystal Microwave Phase Shifter. IEE Electron. Lett. 29(10): 926-928.

[7] Penirschke, A., S. Muller, P. Scheele, C. Weil, M. Wittek, C. Hock, and R. Jacoby. 2004. Cavity Pertubation Method for Characterisation of Liquid Crystals up to 35 GHz. 34th European Microwave Conference. Amsterdam.545-548.

[8] Leuder, E. 2001. Liquid Crystal Displays: Addressing Schemes and Electro-optical Effect. New York: John Wiley and Sons.

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