Scattering parameter based loss characteristics of two monopole antennas for low-band LTE mobile terminals

摘要

In this paper, the loss exhibited by two monopole antennas on a small terminal chassis is investigated. These two vertical quarter-wavelength monopole antennas were designed to operate at 698 - 960 MHz low-band Long-Term Evolution (LTE) and the loss performance was studied numerically at five different locations. The influence of bandwidth characteristics on the loss was also investigated by tuning the impedance bandwidth of the antennas using a matching circuit. This provides narrow-band and wide-band antenna characteristics using the same multiple antenna structure. Results show that the loss of both wide-band and narrow-band antennas located at the center of the terminal chassis are of at least 30% and 7% lower than the loss of antennas at the edges, respectively. It is also shown that when one of the antenna elements is perpendicularly oriented to the other antenna element, the loss can be reduced by up to 56%. On average, wide-band antennas attained lower loss compared to narrow-band antennas over the matched operational bandwidth.