Question 2 120 marks] (a) [10 marks] A copper track on a multilayered printed circuit board (PCB) is 0.8 mm wide and separated from a large ground plane by 1.5 mm. The relative dielectric constant of the homogeneous PCB material (FR-4 epoxy-resin glass-fiber) is 2.5. The arrangement is as depicted in Figure 1. 0.8mm Copper track PCB laminate Page 1 of 3 Ground plane Figure 1 (i) [5 marks] Using "method of image", calculate the capacitance per meter between the copper track and the ground plane. Your answer must include an explanatory diagram to support your calculation. (ii)[2 marks] Why cannot we calculate capacitance of (i) without using "method of image”? (iii) 3 marks] Being a lossy dielectric, if the PCB material also has a conductivity -3 x 10-6 S/m, what is the leakage resistance per meter between the copper track and the ground plane? (b) [10 marks] Two infinite plates, insulated from each other, are maintained at potentials ( and V, as shown in the Figure 2 below. Determine the (i) potential and (ii) electric field distribution for the regions defined by (<<a Note that the del operator in the cylindrical co-ordinate is given by V₁

Fig: 1