This paper describes theoretically the radiation properties of four element microstrip antenna array printed upon a typical ferrite substrate Ni1.062Co0.o2Fe1.948O4 in the presence of normal dc magnetic bias field. In loss-less isotropic warm plasma, this array antenna geometry excites both electromagnetic (EM) and electroacoustic plasma (P) waves in addition to nonradiating surface waves. In the absence of an external magnetic field, the EM - mode and P-mode can be decoupled into two independent modes, the electoacoustic mode is longitudinal while the electromagnetic mode is transverse. Far zone electromagnetic mode and plasma mode radiation fields are derived using vector wave function technique and pattern multiplication approaches. The results are obtained in both plasma medium and free space .Some important antenna parameters such as radiation patterns, radiation conductance and directivity are plotted for different values of plasma to source frequency.