Design Of Microstrip Square-patch Antenna For Improved Bandwidth And Directive Gain
, International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 2(2): 441-444.
Under the condition that the array is relatively accurately calibrated, Optimum Directive Gain (ODG) method in  gets the optimum gain.
According to the actual calibration condition, new method can present a good tradeoff among directive gain, array efficiency, SLL, nulls and robustness against array uncertainty.
Compared with the existing methods, the solution of new constrained optimum directive gain method is more analytical and easier to implement.
The solution of the maximum directive gain is an optimization problem.
of an antenna in a particular direction is defined as ratio of power density in that direction at a given distance to the power density that would be radiated at the same distance by an isotropic antenna radiating the same total power Maximum Directive gain
is defined as directivity of antenna
0 to 40 GHz; and (3) the directive gain of an antenna with various combinations of azimuth and elevation beamwidth.
PHOTO : DIRECTIVE GAIN, G1, AS A FUNCTION OF BEAMWIDTH
However, obtaining extra directive gain
could be at the expense of insertion losses introduced by phase shifters that would decrease the overall antenna gain.
The directive gain
for the element is readily calculated using
For a given incident wave power, the power available from the equivalent generator is the same for all antennas having the same directive gain.
Figure 3 shows the antenna radiation conductance, susceptance and directive gain, for the direction perpendicular to the ground plane, over an octave frequency range from 160 to 320 MHz.