Ref design cuts ZigBee wireless sensor cost to $5
Jennic has introduced a reference design for its JN5139 ZigBee wireless microcontroller which it claimed can reduce the bill of materials cost of modules for wireless sensor networks to under $5.
The cost saving come from elimination of the antenna and RF balun components by using a balanced antenna printed on the circuit board, requiring no additional components to match to the chip’s 200ohm resistive differential RF interface.
By designing the antenna to interface directly to the chip, the balun losses are removed, giving an instant 1.5dB improvement in receive sensitivity and transmit power.
Secondly, the design of the antenna ensures that it has significantly higher gain (around 4dBi) than the ceramic antenna (approximately 1.5dBi) it replaces – due to the design’s larger size, giving higher radiation efficiency, and the lower resistivity of the PCB metallization when compared with the sintered metal commonly used in ceramic antenna designs.
For the crystal, Jennic has used a HC49U surface mounted package measuring approximately 12.5×3.7×4.2mm.