A planar grid array antenna (GAA) at 93 GHz on low cost print circuit board (PCB) with switched beams is proposed. The switched beams are able to be generated by positioning the feeding points properly for a specific coverage. Compared with traditional bulky lens design, the proposed GAA is with much simplified feeding structures. Compared with the switched beam antenna using butler matrix structure, the proposed GAA is with enhanced gain and much reduced size. Compared with the planar transmit array antenna, the proposed antenna is with much reduced size, simple configuration and no assembly issue between the planar lens and the feeds. With substrate integrated waveguide (SIW) feeding structure, the antenna is able to generate 3 beams with a specific coverage of ±19◦ and a peak realized gain of 18.7 dBi. The design concept is promising for switched beam antenna design at 77 GHz for low cost automotive radar applications.