(i) The magnetic field of a TEM plane wave in air can be written H = Ho exp j(2nft-ßx) â. Am¹ Use one of Maxwell's equations to derive a similar expression for E. Also sketch the orientations of H, electric field E and power flux at any instant relative to the x,y,z-axes. (ii) Explain what is meant by the Poynting vector S= EXH, calculate S for the wave of Q3(a)(i) and write down its time averaged magnitude (iii) The wavelength is measured to be 2.5 cm and the rms power flux to be 10(1 + Y) μW/m². Calculate the frequency, the amplitudes of the electric field E, and magnetic field Ho, and state the part of the EM spectrum that the wave occupies.

(i) The magnetic field of a TEM plane wave in air can be written H = Ho exp j(2nft-ßx) â. Am¹ Use one of Maxwell's equations to derive a similar expression for E. Also sketch the orientations of H, electric field E and power flux at any instant relative to the x,y,z-axes. (ii) Explain what is meant by the Poynting vector S= EXH, calculate S for the wave of Q3(a)(i) and write down its time averaged magnitude (iii) The wavelength is measured to be 2.5 cm and the rms power flux to be 10(1 + Y) μW/m². Calculate the frequency, the amplitudes of the electric field E, and magnetic field Ho, and state the part of the EM spectrum that the wave occupies.