antenna operating at 700MHZ, BW>100MHZ, HOW TO DO?

[arthritis]

arthritis 700mhz

antenna operating at 700MHZ, BW>100MHZ, LOW PROFILE is preferred, half power pattern width should be more than 90 degrees, which type of antennas can be the best candidate???

 

[biff44]

You could print a log periodic on a PWB. That would be low profile.

 

[Darren_pan]

well~~~it's another way to fulfill your request that using the microstrip antenna,however,it's different from conventional antenna. you know,microstrip antenna has narrow bandwidth. For spreading hte bandwidth,there're many ways to use,one way is using the air as dielectric substrate,it's very useful to enlarge the bandwidth. then using the EMC feeding,all of you requested can be done.

 

[arthritis]

thank biff44 and darren_pan, I am planning to do it by PIFA, but 700MHZ will make the PIFA a little long, using branches makes it hard to match.

printing a log periodic should be a GOOD idea, i'll try it later.
Using microstrip antenna with air substrate may be a little complex, moreover, 15% bandwidth may a headache.

Added after 2 minutes:

MOREOVER, my CST and HFSS often get very different results for same structure. What can i do then???