PIFA antenna-very urgent

hi sir
I am jayanthi from NIT trichy

in one of yhe IEEE paper the gain at phi=0deg is -2dbi and gain at phi=40deg is 2dbi that is the peak gain is 2dbi at phi=40deg . In IE3d i know how to see the max gain at phi=40deg but while taking measurement after fabricating the antenna
how to test the gain at phi=40deg .please ex[plain me
with regards

using an Omindirectional antenna(Gt=1dB) as the Tx antenna and using a signal generator and feed the power (Pt) to the Tx antenna. with a distance of L, place the one your made as the Rx antenna and feed the power received to a powermeter.
now rotate the Rx antenna horizontally, and note the powermeter read when you get phi=40degree as (Pr).

now, considering FSL model, and the following formula Pt+Gt-FSL=Pr+Gr (all in dB)
FSL=20log(4piR/λ) dB where R is the distance between Tx and Rx, λ is the wavelength of the signal from signal generator and in meter.

hope this helps..