For practical consideration, the almost full space coverage is usually satisfied with the combination of two identical omnidirectional antennas
[1-6], which are placed perpendicular to each other on satellite platform, or using two identical hemispherical antennas [7-10], where one of them is placed top platform and the other is placed to bottom platform of the satellite.
Figure 16 shows the significant outperformance of our directional antenna scheme as compared with the omnidirectional antenna
For common WPAN system, omnidirectional antennas
are equipped by all DEVs.
The C-band terminal can display so-called be carried in a soldier's backpack with the entire ensemble including a ruggedized laptop, receiver; omnidirectional antenna
and data processing unit; plus replacement rechargeable batteries.
In the simulation, vertically polarized omnidirectional antennas
with 5 dBi of gain are used, and the heights of transmitter antenna and receiver antenna are 2.2 m and 1.2 m, respectively.
However, using an omnidirectional antenna
like a monopole antenna has a possibility to transmit signal in many directions.
The PDT-100, which weighs only three pounds, is extremely rugged and durable, due in part to an omnidirectional antenna
and lack of moving parts.
For instance, KARK Channel 4 has an omnidirectional antenna
that is used to create live feed for the station.
In other words, though the proper use of directional antenna gives a high compensation to received power, the distinctions of the radio channels characteristics between applying directional antenna and applying omnidirectional antenna
are not clear.
Recently, the demand for a vertically polarized and low-profile omnidirectional antenna
with wide bandwidth reminds the authors of the prospective features of the Quadripod Kettle Antenna (QKA).