# Current element and λ/2 antenna

"The intensity of the field radiated at a distance r >> λ from a current element Idz is given by the magnetic filed intensity $$\hat{H} = \frac{I }{2\lambda r} sin(\theta) dz$$ Find the electric field strength in free space at a point 1km from a λ/2 dipole in a direction normal to its length when fed with a current of 0.1A (rms) at its center. Given that the radiation resistance of the λ/2 dipole is equal to 74 ohm."

I was given this question as an assignment, but I'm struggling to find an accurate solution. Could anyone outline the methods used to solve this problem?

• Thanks for admitting that it is a homework assignment. Please show what attempts you have made at solving it. Jul 13 '20 at 19:33
• I just multiplied (H) vector by the intrinsic impedance of free space and substituted λ/2 for dz to get (E) vector. I also substituted the max. value of the current given in rms for (I) in (H) and 10^3 for (r). Then, I got an (E) expression as a function of (theta), but I'm not sure if this is correct or what I'd do with the radiation resistance value of the half-wavelength dipole. Jul 13 '20 at 19:51