Differential pair feed line design for a millimeter-size antenna for in-body/out-body dual usage

Recently, application of wireless communication technology for the medical field has advanced. We are aiming to realize millimeter-size ultra-small sensor for tablet equipped with chip that can wirelessly communicate in in-body and out-body. The size of antenna of this wireless communication chip is limited and the antenna is used for both in-body and out-body communication. Moreover, for evaluation in in-body synthetic medium (water), long feed line is necessary to reduce the effect of water surface. This feed line is necessary not to be affected by the medium. Therefore, we propose the antenna with broadside coupled differential pair that is unsusceptible by surrounding medium.