<< Calculus`VectorAnalysis`
<< Graphics`ParametricPlot3D`
<< Graphics`Animation`
SetCoordinates[Cylindrical[r, φ, z]]; 
    Clear[r, φ, z, a, q, ϵ];
rr = {r, φ, 0}; aa = {a, 0, 0}; 
    rp = Sqrt[r^2 + (a/2)^2 - 2*a/2*r*Cos[φ]]; 
    rm = Sqrt[r^2 + (a/2)^2 - 2*a/2*r*Cos[Pi - φ]]; 
    pp = q*aa;
vk = 
        1/(4*Pi*ϵ)*
          DotProduct[rr, pp]/r^3;
vg = 
        1/(4*Pi*ϵ)*(q/rp - 
              q/rm);
a = 1; q = 1; ϵ = 1;
SetDirectory["z:"];
Export["Cylindrical.gif", 
      Table[Show[
          GraphicsArray[{CylindricalPlot3D[
                vk, {r, 0, h}, {φ, 0, 2*Pi}, 
                BoxRatios -> {1, 1, 1}], 
              CylindricalPlot3D[vg, {r, 0, h}, {φ, 0, 2*Pi}, 
                BoxRatios -> {1, 1, 1}]}], ImageSize -> 500], {h, 
          0.1, 3, 0.1}]]