ATZB-900-B0 Datasheet, PDF (18/20 Pages) ATMEL Corporation – ZigBit™ 700/800/900 MHz Wireless Modules

Specifications
Figure 3-5. FCC/CE compliant RF reference design with RP-SMA connector recommended for ATZB-900-B0
3.6.1
Multiple factors affect proper antenna match, hence, affecting the antenna pattern. The particular factors
are the board material and thickness, shields, the material used for enclosure, the board neighborhood,
and other components adjacent to antenna.
General recommendations
„ Metal enclosure should not be used. Using low profile enclosure might also affect antenna tuning.
„ Placing high profile components next to antenna should be avoided.
„ Having holes punched around the periphery of the board eliminates parasitic radiation from the board
edges also distorting antenna pattern.
„ ZigBit 900 module should not be placed next to the consumer electronics which might interfere with
ZigBit 900's RF frequency band.
The board design should prevent propagation of microwave field inside the board material. Electromag-
netic waves of high frequency may penetrate the board thus making the edges of the board radiate,
which may distort the antenna pattern. To eliminate this effect, metalized and grounded holes must be
placed around the board's edges.
ZigBit™ 700/800/900 MHz Wireless Modules
3-11
8227C–MCU Wireless–06/09