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 scheme.
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).
