**5. References**


[4] Nakhkash, M., Yi Huang, Al-Nuaimy, W., & Fang, M.T.C., (2001) An Improved Calibration Technique for Free Space Measurement of Complex Permitivity, IEEE Transactions on Geoscience and Remote Sensing, Volume 39, Issue 2, pg 453-455.

110 Dielectric Material

**3. Further research** 

**4. Conclusion** 

**Author details** 

Mohd Fareq Abd Malek

**5. References** 

Other boards fabricated using different agricultural waste materials should also be investigated. This will also depend on the waste material's availability, based on the geographical region and type of agricultural/economic activities. On the other hand, the current scope can be expanded to evaluate boards with different thicknesses, as MUT's thickness could affect measurement accuracy. It is also evident that improvement on the

A systematic procedure to fabricate and evaluate custom particle boards made from two types of agricultural waste product is explained in detail. In total, six variation of waste boards are evaluated, and they are fabricated using different paddy waste types and different bonding resins, i.e. Urea Formaldehyde (UF) and Phenol Formaldehyde (PF). Two standard setup and procedures for measuring their dielectric properties between 2.2 GHz and 3.3 GHz are presented and compared. The results, calibration and factors influencing measurement accuracy are then discussed. Rice husk-based MUTs are measured to be higher in terms of dielectric properties compared to rice straw-based MUTs. This is mainly due to the former's small particle size, enabling a larger surface area which absorbs more test signal. Comparison of two measurement methods presented shows a good agreement, with uncertainties of less than 15 %. The measurements have also proven that MUTs fabricated using PF is higher than UF due to the ability of the former to absorb moisture. The measurement results presented will be potentially useful in encouraging the use of such

measurement setup is relevant, especially on the free space measurement technique.

sustainable, renewable materials at microwave frequencies.

Wee Fwen Hoon, Soh Ping Jack and Nornikman Hasssan

*School of Electrical Systems Engineering, Universiti Malaysia Perlis (UniMAP), Malaysia* 

Antennas and Propagation, Volume 151, Issue: 3, pg 271-276.

for Cyclone Gasifier. Journal of Apllied Sciences 8(4): pg 622 – 628.

[1] Jayanthy, T., & Sankaranarayanan, P.E., (2005) Measurement of Dry Rubber Content in Latex Using Microwave Technique. Measurement Science Review, Volume 5, Section 3. [2] Gagnon, N., Shaker, J., Roy, L., Petosa, A., & Berini, P., (2004) Low Cost Free Measurement of Dielectric Constant at Ka Band, IEEE Proceedings - Microwaves,

[3] Mohamad Yusof, I., Farid, N.A., & Zainal, Z.A., (2008) Characteristization of Rice Husk

*School of Computer and Communication Engineering, Universiti Malaysia Perlis (UniMAP), Malaysia* 


at Milimeter Wavelength, IEEE Instrumentation and Measurement Technology Conference Proceedings. (IMTC 2007), pg 1-5.

**Chapter 6** 

© 2012 Belous, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

© 2012 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution,

distribution, and reproduction in any medium, provided the original work is properly cited.

The development of modern telecommunication systems calls for the creation of novel materials with a high level of electrophysical parameters in the MW range. These materials must have in the MW range a high permittivity (ε ≥ 20), a low dielectric loss ( tg δ ≤ 10-3 – 10-4) and a high thermostability of electrophysical properties (temperature coefficient of permittivity (TCε) or resonant frequency (f) 10-6K-1). Such materials can be used in the development of resonant elements of radio-frequency filters, solid state oscillators, substrates for hybrid MW circuits, allow the size of communication systems to be greatly reduced and improve their parameters. Moreover, the use of them reduces the manufacturing and

The choice of the permittivity value of MW materials is largely determined by the frequency range of the operation of communication systems, the type of exciting wave and the requirement of the optimal size of dielectric element. The value of ε determines the size of radio components. The influence of microminiaturization is based on the fact that the electromagnetic wavelength in dielectric decreases in inverse proportion to √ ε. Therefore, in the decimeter wave band, high-Q thermostable materials with high permittivity value (ε ≥ 80-600) are required, whereas in the centimeter and millimeter wave bands, thermostable materials with ε ~ 15-30 but with extremely high Q (Q× f ≥80000, where Q = 1/ tg δ and f is

It should be noted that low dielectric loss in the MW range 109 – 1011 Hz is characteristic only of optical and infrared polarization mechanisms. Other polarization mechanisms give rise,

In the case of optical polarization, dielectrics are characterized by a low negative temperature coefficient of permittivity (TCε ~ 10-5K-1). However, the dielectric contribution of optical

and reproduction in any medium, provided the original work is properly cited.

**Microwave Dielectrics Based on** 

**Complex Oxide Systems** 

Additional information is available at the end of the chapter

operating costs for modern communication systems.

A.G. Belous

http://dx.doi.org/10.5772/51168

frequency in GHz) are needed.

as a rule, to considerable dielectric loss [1].

**1. Introduction** 

