Quatech HD500 User Manual

100-8510-110 

2/21/2011 

29 

PCB Embedded 

– This approach embeds an antenna design into the host PCB. 

This approach is very common with add-in WiFi cards (CF, PCMCIA, SDIO, etc.) 
as it requires no external connections and is the cheapest production approach. 
The lower production cost requires significant development cost and lack of 
performance and flexibility. 

Chip 

– The integration of a chip antenna is simple and requires a relatively small 

footprint on the host system, however, it does suffer from the same limitations of 
flexibility and performance seen with the PCB embedded approach. There are 
relatively large numbers of suppliers of this type of antenna; there is also a range 
of configuration and performance options. 

– This approach is similar to the flying lead solution for external 

antennas. The difference is that the form factors are smaller and provide a range 
of chassis and board mounting options, all for internal use. This approach suffers 
less from the performance and flexibility limitations of the other approaches, 
since the location of the antenna it not determined by the host PCB design. The 
assembly of a system using this approach maybe slightly more complex since 
the antenna is not necessarily mounted on the host PCBA. 

The importance of this design choice cannot be over stressed.  It can in fact be 
the determining factor between success and failure of the WiFi implementation.  

There are several factors that need to be considered when determining location: 

  Distance of Antenna from radio 

  Location of host system 

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Proximity to RF blocking or absorbing materials

 

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Proximity to potential noise or interference

 

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Position relative to infrastructure (Access Points or Laptops)

 

  Orientation of host system relative to infrastructure 

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Is it known

 

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Is it static

 

To minimize the impact of the factors above the following things need to be 
considered during the development process: 

  Minimize the distance between the radio and the location of the antenna. The 

coaxial cable between the two impacts the Transmit Power and Receive 
Sensitivity negatively. Quatech recommends using 1.32-1.37mm outer 
diameter U.FL coaxial cables. 

  Minimize the locations where metal surfaces come into contact or are close 

to the location of the antenna. 

  Avoid locations where RF noise, close to or over lapping the ISM bands, may 

occur. This would include microwave ovens and wireless telephone systems 
in the 2.4GHz and 5.0GHz frequency range. 

  Mount the antenna as high on the equipment as possible.