Missiles with onboard radars must use durable high-temperature materials for the radome, which is the term for the covering that protects a radar or other type of antenna. One material that can be used for a high-temperature radome is alumina, a ceramic (A1,02), which has a relative permittivity of E, = 9.6 at a frequency of f = 26 GHz. Alumina is non-magnetic (u, = 1). (a) Calculate the wave impedance n of alumina (the ratio of the electric-field magnitude to the magnetic field magnitude) at 26 GHz. (b) What is the propagation constant B of a TEM wave in alumina at f = 26 GHz? (c) As you will find later in the course, a slab of lossless dielectric material one-half- wave thick can transmit essentially all of the TEM-wave energy normally incident upon it. If you wish to make a half-wave-thick radome sheet out of alumina at 26 GHz, how thick must it be? Express your answer in mm.