Circuit model and analysis of antenna-in-package

This letter presents a circuit model of the antenna-in-package (AiP) employing the via holes to connect the antenna ground and the system ground. A closed-form expression for the inductance of ground via is provided in case that two ground vias are arranged under the non-radiating edge of the AiP. The new expression takes account of the radius and length of the vias, the relative positions of the vias and the distances between the vias and the feed point of the antenna. Then, the influences of the vias on the performance of the AiP are analyzed using the model. It is found that the bandwidth of the AiP can be improved effectively by properly arranging two via holes under the non-radiating edge of antenna. The simulated results agree with the modeled results.