Radiation characteristic of mono-conical antenna for wideband electromagnetic field generation

A new type of tears-shape antenna composed of spherical element and biconical antenna element is proposed as an transmitting antenna at frequencies above 1 GHz. The antenna is named as tears type antenna, and its characteristics are analysed by the finite integration (FI) method that is one type of a numerical method. As a result, it is clarified that the frequency characteristics of the radiation was improved with a reinforcement material of 5 mm thickness. The electric field increased from 5 dB to 10 dB in the case of the improved antenna compared to the antenna without the reinforcement material. The electric field also increased by 3 dB except for the direction of the maximum radiation such as the direction of thetas =90 degrees in a case where the distance from the centre of the antenna was 1 m the near-field condition. The value of the voltage standing wave ratio (VSWR) was equal to or less than 2 at frequencies of 1 - 7 GHz. It is confirmed that the reinforcement material made the antenna strong structurally, and achieved the broadband of the antenna and a high radiation of electric fields.