This article presents a new antenna structure using truncated ground walls (TGWs) for a gain enhancement implementation. The proposed antenna with TGWs is analyzed by an array of magnetic currents where the edge slot radiation of the proposed antenna is included. Also, the radiation at edge slots is operated by TGW, resulting in further enhancement for the antenna gain. To verify the proposed antenna with TGWs, an antenna module with a balun feed network was implemented and tested. The fabricated antenna gain was 10.1 dBi, and overall volume was 50 x 50 x 6 mm(3) (0.97 lambda(0) x 0.97 lambda(0) x 0.11 lambda(0) at 5.8 GHz), which show a high gain to volume ratio compared to the conventional structures. The measured 10 dB impedance bandwidth (IBW) was 5.7% from 5.65 to 5.98 GHz, and 3 dB gain bandwidth was about 14% from 5.2 to 6.0 GHz.