The electrically compact microstrip antenna is studied with analysis of different modes of transmission. The design of a rectangular microstrip antenna (RMSA) is implemented for a Bluetooth band. The parallel shorting plate is inserted to reduce size which in turn shifts the null point of the patch to the position of the plate and excited the mode below its fundamental operating mode i.e. TM00 mode. IE3d simulator is used to analyze the mode of transmission in terms of the current path. Simulated and measured results validate the hypothesis made of the fact of the mode of transmission.