Will a full-band signal jammer equipped with a directional antenna reduce interference to the side and rear?
In different application scenarios, a full-band signal jammer can usually be configured with an omnidirectional antenna or a directional antenna to achieve differentiated control of the signal interference effect. Compared with the "360° uniform coverage" of an omnidirectional antenna, a directional antenna mainly concentrates energy to emit in a specific direction, and has a stronger long-distance interference capability. But this often leads to a common question:
"After using a directional antenna, will it not interfere with the side and rear?"
Understand that the "directivity" of a directional antenna is not "singleness"
Directional antennas, as the name suggests, have obvious directionality. For ease of understanding, it is sometimes compared to flashlight lighting - the light is concentrated in the front, and there is no light at the back and sides. But in fact, the propagation characteristics of wireless signals are far more complex than light, and this analogy is prone to misunderstanding to a certain extent.
If we place the shielding device equipped with a directional antenna in a microwave darkroom and perform 3D signal modeling with professional equipment, we can find that:
**The signal strength in the front area (main lobe)** is the strongest and the interference effect is the most significant;
The sides and back (sub-lobes and side lobes) still have wireless signals transmitted. Although the signal strength is low, it still has a certain interference ability;
Therefore, directional antennas cannot be completely "interference-free" on the sides and back, but the interference range and effect in these areas are limited.
Why are there side lobes?
Any actual directional antenna (such as flat antenna, Yagi antenna, parabolic antenna, etc.) cannot achieve the ideal "single-direction radiation". In addition to the main lobe, there will be multiple side lobes. The distribution and strength of these side lobes in space depend on:
Antenna structure design (array type, size)
Material properties and manufacturing process
Operating frequency range
Installation angle and environmental reflection, etc.
Precautions when selecting directional antennas
When selecting a suitable directional antenna for the cell phone signal jammer, the following key indicators need to be considered:
Main lobe angle: determines the coverage width of the main interference direction;
Side lobe suppression ratio: the lower the energy proportion of the side lobe, the weaker the interference to the side and rear;
Gain: higher gain means a longer interference distance, but at the same time the beam is narrower;
Antenna adaptation band: ensure that the frequency range covered by the jammer is matched (such as 2G/4G/5G/WiFi/GPS, etc.).
Full-band signal jammers equipped with directional antennas can indeed significantly enhance the interference effect in a specific direction, but it does not mean that there is no effect on the side and rear. The presence of side lobes will still cause some interference in these directions, but the signal strength and coverage distance are much weaker than the main direction.
Therefore, in practical applications, it is necessary to scientifically select and reasonably arrange the antenna position and angle according to the interference requirements, site layout and target direction, so as to achieve more efficient and accurate signal control.
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