Design of an ultrawide-band TEM horn antenna with a microstrip-type balun

An exponentially tapered ultrawide-band transverse electromagnetic (TEM) horn antenna having a microstrip-type balun is designed. The balun is used to improve the impedance characteristic of a TEM horn antenna. The measured bandwidth for VSWR less than 2.0 ranges from 67.94 to 1573.9 MHz. The bandwidth of the proposed TEM horn is three times wider than that of the linearly tapered TEM horn. The designed antenna can be used not only for electromagnetic compatibility measurement but also for broad-band communication system.