Truncated corner patch antenna

[antenna9071]

Can someone explain the theory why truncated corner can give circular polarization?

Anyone knows any articels or books there I can read about it?

 

[DenVo]

within a truncated patch the horizontal and vertical edge will be excited. The horizonal electromagnetic field vector and the vertical em- field vector are 90° out of phase, which produce the circular polarization.

by the way the 90° phase shift between h- and v- vector or vice versa defines also if it is RHC (right hand circular) or LHC.

if circular polarization is desired by using a truncated patch, please also take care of the field vector strength from h and v. If both are not exactly the same you will generate elliptical polarisation.

check this book: Microstrip antennas: the analysis and design of microstrip antennas and arrays

for polarization basics: Antenna Theory: Analysis and Design from Balanis

greeds DenVo

 

[DenVo]

the following sentence is not true:

if circular polarization is desired by using a truncated patch, please also take care of the field vector strength from h and v. If both are not exactly the same you will generate elliptical polarisation.

so its right:

if circular polarization is desired by using a truncated patch, please take care that the field vectors are excatly 90° out of phase, otherwise you would generate elliptical polarization. Unequal vector stength's in this case has no impact on the resulting polarization. Only the start angle and the resulting vield vector strenght will be influenced.


Sorry

 

[AndreyG]

to DenVo:

I think you are correct in the essence of your warning though:

the designer should watch for elliptical polarization. It is easy to get it elliptical by cutting the opposite corners of the patch but there is only one size of the cuts when polarization becomes circular.