: Nowadays , by extending wireless communications and using variant antenna on a device , miniaturization antenna will be more important , specially in platforms with restricted sizes such as unmanned aerial vehicles (UAV).Generally an antenna is considered to be electrically small (ESA) , when its maximum dimension is about less than a quarter of free space wavelength . Since to exist large wavelength in the low frequency , it is much more considerable to design ESA in VHF or UHF band. Narrow bandwidth and low efficiency are disadvantages that caused by miniaturization . One of the key parameter for electrically small antenna is the radiation quality factor (Q) . A low Q antenna is desirable for many applications , thus achieving minimum limits of this parameter is the historical challenge in designing ESAs. There are many different methods for miniaturization of antennas . One of them is using characteristic mode theory (CMT) that had been introduced by Garbacz for the first time and then Harrington expanded it for the perfect electrically conductor bodies. CMT has been applied to antenna analysis and synthesis problems . In this theory , total response of antenna is decomposed to finite sum of eigen functions (eigen current or eigen fields) . So by obtaining proper physical insight can be useful for designing ESAs. In this thesis a wideband small UHF microstrip antenna with monopole like radiation pattern is desiged , simulated and constructed that is compareable to a blade antenna of aircraft . The most of blade antenna have omnidirectional or monopole like pattern . The results of measurement and simulation are compatable . Dimensions reduction and bandwidth improvement are achievements . Key Words: Small Anten na , Characteristic Mode Thoery , Monopole Like Pattern , Blade Antenna