Summary
International Symposium on Antennas and Propagation
2010
Session Number:4FC1
Session:
Number:4FC1-2
Evaluation of the Performance of a Multi-band Antenna for On-board Applications
Vijayashree T.Bhat, Vedaprabhu B, K.J.Vinoy,
pp.-
Publication Date:2010/11/23
Online ISSN:2188-5079
Summary:
Modern life depends so much on wireless technologies that one can no longer afford to be offline for long, even during flights. Although not yet proliferated, the aircraft industry has already begun efforts to introduce in-flight wireless connectivity [1, 2]. The antenna requirements for these access points within the cabin are not as stringent as antennas placed outside the aircraft. Yet planning of wireless access points in this scenario, even for mobile phone access, is complicated by the fact that the aircraft, particularly long-haul ones, are expected to conform to wireless standards currently existing in different parts of the world. It is therefore challenging to integrate access points for wireless technologies such as AWS, GSM and various WiMax and WLAN bands operating at 1710-1755 MHz, 1805-1880 MHz, 1900-1990 MHz, 2110-2170 MHz, 2.4-2.5 GHz, 5.15-5.35 GHz, and 5.45-5.85GHz. This group has recently proposed a multifunctional microstrip antenna with two U-shaped slots to achieve the dual wideband operation to meet the above requirements [3, 4]. The dimensions and locations of the U-slots were designed for locating its operational bands. A thick substrate used there, which in fact uses existing aircraft panel material and helps broaden the individual bandwidths. We have found that the experimental result for this antenna meets all current requirements for incabin wireless communication needs. However the cabin of an aircraft cabin is usually a metallic structure, with a number of other metallic objects such as seat supports in close vicinity. Hence the performance of such an antenna will have to be validated in a cabin-like environment and preferably in a real cabin. The field intensity variation in an aircraft differs from many other structures and hence on-site measurements are required to analyze the performance of the antenna inside the cabin [1]. In this paper we report experiments towards such a validation. Very few in cabin measurements are done for GSM and CDMA wireless networks but in this paper we report measurements over a larger range of frequencies (1.8GHz to 5.4GHz), using a portable network analyzer. The field distribution is measured using a small field probe antenna placed at different locations in an x-y plane and corresponding readings are noted using a portable network analyzer. The test antenna (U-slot antenna) acts as the transmitter and a specially designed UWB monopole antenna acts as the field probe receiver.