Contents I. INTRODUCTION
Composite and polymer material were attracting in all branches of engineering field and yet the uniqueness of the technology now more related to the implementation of green technology. The criteria stated that green technology product should use and conserves the natural resources and implemented the raw resources can be renewable [1], , [3]. In composite technology, the different materials are combined toproduce new material while minimizing the effect of deficiencies. By applying the composite technology the designer or researcher not only enhancing the behavior of the composite material itself but also have variety on selection of manufacturing process compared to conventional type. One of the branches of the composite knowledge is Wood Plastic Composite (WPC). The WPC is a product that partially mixed between wood and thermoplastic. The thermoplastic polymer can be either Polyethylene (PE) or Polypropylene (PP). Since the melting point for polypropylene is very high up to 180 degree Celsius there for a lot of researcher where focusing on the usage of Polypropylene (PP) as a substrate laminator. The selection of wood plastic composite(WPC) is based on the capability of the material for its high durability, very low maintenance and can be reusable, high relative strength and stiffness, less prices compare to others currently commercial substrate and it consume natural resources[4]. Besides that, WPC offer some advantages on strength points including the resistance in opposition to biological deterioration especially for outdoor applications where untreated timber products are not suitable, the high availability of fine particles of wood waste is a main point of attraction which guarantees sustainability [5]. The usage of WPC are more related to structural building application whereby it mostly been used in making profiles, sheathings, decking, roof tiles and window trims. WPC capability were not stiff as a solid wood, but if compared to unfilled thermoplastic the composition and density offer more stiffer behavior. In fact, the usage of WPC do not required any fastener or any resin as required like conventional wood. So not only stiff and good on strength WPC also friendly on ecological system yet apply green technology system. The whole idea of the research to find the dielectric properties of the substrate and its relation towards electromagnetic behavior, so the value of dielectric constant and loss tangent seem to be very significant since it measure how the radio frequency penetrate through the proposed WPC substrate. Microwave dielectric properties can be expressed by complex permittivity and it will give some good info especially for researchers dealing with antenna and filter design [6], , [8], [9]. The permittivity and loss tangent value will give the loss obtained by the substrate and it will determine the substrate if there any RF attenuation occurs. The value relies on storage and loss of energy contained in a material or substrate. The knowledge of a material's dielectric property is necessary in determining its suitability for a specific application. FR4 material is widely being used as a substrate on most of the antenna design and the dielectric properties of the material dielectric constant is alias between 4.3 to 4.9 [10], [11]. The usage of the FR4 suffer on strength and temperature on certain application due to the fabrication process itself while the new proposed leucaenaleucocephala Wpc board offer some immunity to the greater on strength and temperature to about 180° C of melting point and this will be great on certain application especially on high power application later. The main issue of leucaenaleucocephala WPC board is about strength and the filler mixture between polymer or polypropylene with the percentage of filler will contribute to the unknown dielectric properties on electromagnetic application that will be crucial parameter value especially on antenna applications since the dielectric value will give of the researcher some value to be used when modeling their design in simulation or on calculation. The contain of lignin or fiber inside of the leucaena leucocephala filler will contribute to the strength and different value on dielectric Constance value. Good on strength or mechanically was not lead to get good reading of dielectric constant and loss tangent value, the issue on fabricating process and mixture density will contribute on different reading of dielectric constant and loss tangent value. Leucaena leucocephala is popular among Malaysians as tree that can reduce the symptoms of high blood pressure. Malaysians known this tree as ‘Petai Belalang’ and the tree was originally grow in central America and Mexico spread all around the world including Asia and Malaysia is one of the country that have this tree grow all around its land. The tree was easy to grow and the application of the is still neglected and underutilized. The tree can be harvest in 3 years of age to be used on a lot of application including pulp and paper industries and manufacturing of packaging material. The mixing of the polypropylene with leucaena leucocephala filler will give some strength to the substrate structure and it was also echo green technology since it will used some amount of tree that mix with polymer.
