I think Printed Antenna ( array microstrip antenna)

microstip patch array antenna is basically ,thecollection of antenna that give the double directive gain

The source of radiation for rectangular microstrip radiator is the electric field that is excited between the edges of microstrip element and the ground plane.The fields are excited 180 degree out of phase between opposite edges.Each edge therefore radiates an omnidirectional pattern into half space above the ground plane.The opposing edges are excited out of phase but their radiation adds in phase normal to the element.

For more details see Antenna Engineering handbook by Johnson and Jasik.

Thanks.

microstrip circuits can radiate