Characterization of 50–5000MHz UWB printed antennas with different number of arms

In this paper, compact printed ultra-wide band (UWB) antennas with different number of arms are investigated and characterized numerically. As the antennas are proposed to be applied for UWB communication systems such as surface penetrating radar (SPR), they have to provide an ultra-wide band response due to narrow period pulse used by the application. The properties of antennas that are designed to have frequency range of 50-5000MHz for Voltage Standing Wave Ratio (VSWR) less than 2 and size-improved from the preliminary design are characterized with different number of arms and compared each other for some parameters including reflection coefficient (S₁₁), VSWR, gain and radiation efficiency. The optimization for antenna with additional arm is performed in terms of resistive loading application in all ends of arms and adding abrupt transitions onto additional arms. The proposed antennas are designed with 50 Ω microstrip line feeding technique and deployed on FR-4 Epoxy substrate with overall size of 50mm × 41.2mm, relative permittivity of 4.3 and thickness of 1.6 mm. From the result, it shows that the proposed antennas achieve good performance i.e. reflection coefficient (S₁₁) <; -10dB in the frequency range of 50-5000MHz, where for the mono-arm antenna has a good achievement for lower frequency bands (<;1.1GHz) and higher frequency bands (>;2.3GHz) whilst for the dual-arm antenna has a good response for pass frequency bands (1.1GHz-2.3GHz). The gain and radiation efficiency of antennas are almost similar each other where the gain of dual-arm antenna as well as radiation efficiency are higher than the mono-arm antenna for frequency ranges higher than 3.5GHz.