Since nodes using
directional antennas are nearly invisible to nodes that are not positioned in the direction the antenna is aimed at,
directional antennas should be used only for very small networks.
While using
directional antenna at BS, it is essential to have reliable understanding of radio propagation characteristics of transmission path between BS and MS that leads to the design of effective signal processing techniques [1].
Table 1: Comparison of some parameters of
directional antennas. Frequency Boresight 3 dB beamwidth Front-to-back (GHz) gain (dB) (degree) ratio (dB) Conical antenna with elliptical aperture and reflector 3 5.1 98.3 -19.4 6 8.0 66.8 -14.9 9 7.0 103.6 -18.0 12 7.2 96.5 -20.2 15 7.8 73.9 -26.0 18 6.8 88.0 -18.0 Semiplanar conical antenna with elliptical aperture and reflector 3 4.6 114.5 -19.5 6 8.5 50.7 -28.0 9 7.7 87.9 -15.5 12 6.6 90.5 -15.8 15 7.1 66.4 -17.0 18 5.8 85.0 -15.0 Planar
directional antenna 3 5.3 98.6 -14.9 6 7.6 65.4 -18.0 9 7.8 66.1 -16.5 12 8.3 42.7 -18.0 15 6.6 66.9 -16.5 18 6.4 70.0 -15.5
Moreover, the comparison of the dissimilarity among sectors of a
directional antenna and an omnidirectional antenna is shown in Figure 13 and Figure 14.
Quantitative advantages of using: a) planar and b) reliable network topology as well as c)
directional antennas for interference mitigation, have been thoroughly discussed in [9].
After all, unlike previous research, this paper deals simultaneously with the problems of both multicast communication and steerable
directional antenna in 60GHz mmWave wireless networks for the first time.
The top-mounted
directional antenna must be mounted as far forward and as close to the centerline of the airframe as possible, and must be installed such that the horizontal base falls within a certain longitudinal and latitudinal axis while in level flight.
The system consists of a laptop, multi-band receiver, UHF modem, antennas, cables, software and a Mobile
Directional Antenna System.
Other options include a 7-GHz tracking generator, a GPS receiver and antenna, a spectrum monitor with spectrogram record and playback functions, support for a USB power sensor, a data sanitation feature, an 8-GHz
directional antenna, and a power connector for an RF probe.
While a single top-mounted
directional antenna will work, Garmin recommends the optional bottom-mounted, L-band monopole, omni-directional antenna for aircraft sporting fixed landing gear.
Xirrus makes a 16-radio controller with an integrated
directional antenna array, which provides a ton of capacity.
