hyzhao11 & caucatc,
Track down a copy of ICAO Annex 10 Vol 1. (current amendment is 84). There are example diagrams in Attachment C pages 9, 10 & 11 that show the LLZ & GP dimensions for critical and sensitive areas.
For other antenna types you need to speak with the equipment manufacturer to get the correct figures.
As has been stated above, the size of the aircraft operating at a particular airfield is only one factor in determining the dimensions of the areas.
You also need to consider the technical safeguarding of the LLZ and GP sites, which involves thinking about the effects that buildings, fences and other metal structures can have on the beam formation for ILS systems. Trees (foliage, and whether wet or dry) can also have an effect as can the water table under the surface. All of these need to be considered when planning for an ILS installation. If, after an ILS enters service, there are unexpected alarm conditions, all of the above need to be re-examined to see if "something has changed" in the environment near an ILS installation.
For one set of criteria for Technical Safeguarding have a look at CAP 670 (available here:
http://www.caa.co.uk/docs/33/CAP670.PDF) section GEN02.
Hope that helps.
Regards
ST