External Antenna and Internal Antenna
l External
antennas
External antenna can be divided into omnidirectional
antennas and directional antennas according to the different orientations of
the radiation source in the radiation source field.
Omni-directional antenna indoor space radiation pattern
l Omni-directional
antenna:
It is mainly manifested as a 360° uniform radiation
source, which is usually called non-specificity, and on the vertical pattern,
it is mainly manifested as a beam with a certain width. Under normal
circumstances, The smaller the total lobe width, the larger the gain. The
external omnidirectional antenna mainly includes:
l Glass suction
cup antenna
l Fiberglass
anti-corrosion antenna
l Hot melt glue
stick antenna.
l Directional
antenna:
Directional antenna: refers to an antenna that sends and
receives radio waves particularly strongly in one or more special directions,
while sending and receiving radio waves in other directions is zero or very
small. The purpose of selecting a directional transmitting antenna is to
increase the reasonable utilization rate of radiation intensity and improve
safety; the key purpose of selecting a directional receiving antenna is to
improve receiving sensitivity and anti-interference. External directional antennas
mainly include:
l Tablet antennas,
l Yagi antennas
l log-periodic
antennas.
l Internal Antenna
Internal antenna refers to the general term for antennas
that can be placed inside the device. Built-in antennas include:
l FPC antennas
l PCB antennas
l Spring antennas
l Porcelain patch
antennas
l Laser direct
forming technology (LDS)
l Metal spring
sheet antennas.
Conclusion: When selecting
a suitable antenna for a machine or equipment, it is first necessary to choose
a internal or an external antenna based on the product structure. The main
features of the external antenna and the internal antenna are as follows:
l External antenna
High gain, little harm from the surrounding environment,
can be used as a standard product, save development progress, and do not occupy
indoor space
l Internal antenna
The gain is relatively high, the processing technology is
perfect, the delivery consistency of the product is good, it is built in the
equipment, it is beautiful, and it does not need to be independent for three
defenses, it is greatly affected by the surrounding environment, and generally
needs to be customized in combination with the product itself
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