In Low Power Wireless Systems, good Antenna design is required to realize good range performance.
Without an antenna it is impossible to transmit data over a long distance range. Undeniably, of all the elements in a wireless systems, the Antenna is the most difficult to design and optimize: antenna’s performance is closely dependent on variables such as the dielectric constants, proximity to other components, and materials properties.
Finally, antenna measurement and characterization requires sophisticated and expensive test equipment, which may not be readily available.
The following will assist the designer in maximizing system performance.
The RF ground pin should be connected to a ground plane which should shield the aerial connection and the PCB layout around the aerial track itself should be such as to give a 50 Ohm impedance.
The aerial should be kept as far away from sources of electrical interference as physically possible. The specified power supply decoupling capacitors should be placed close to the module as possible and have direct connections to the relevant pins.
The antenna ‘hot end’ should be kept clear of any objects, especially any metal as this can severely restrict the efficiency of the antenna to receive power. Earth planes restricting the radiation path of the antenna will also have the same effect.
The best range will be achieved with either a straight piece of wire, rod or PCB track λ¼ wavelength Increased range may be achieved if this λ(lambda)¼ wave antenna is placed perpendicular to and in the middle of a solid earth plane measuring at least 16cm radius. In this case, the antenna should be connected to the module using 50 Ohm coaxial cable and the PCB track layout tips given above should be observed.
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