Multiband Cross-Shaped Inverse Triangular Notch Antenna for Radio Shadow Zone Communication

Abstract

This paper proposes a multiband cross-shaped inverse triangular notch antenna on a circular ground plane for a radio shadow zone mobile communication design for a broadband repeater antenna in the firefighting band for in-building mobile communication. To arrive at the broad and multi-bandwidth reflection coefficients, methods are considered for optimizing the cross-shaped notch antenna with an inverse triangular structure and the circular ground plane. The measured reflection coefficients are observed −10 dB lower in the firefighting band (440–450 MHz) and the mobile repeater band (890–2,450 MHz), and they agree well with those obtained through simulation. The desired omni-directional patterns are obtained in the firefighting band, even though the radiation patterns in the Wi-Fi band have directivity from 10° to 15° and from −10° to −50°. The measured radiation patterns and gains also agree well with the predictions.