Abstract: A matching circuit system includes a first inductor, a first capacitor, a second inductor, a second capacitor, a third inductor, and a third capacitor. The first inductor has a first terminal and a second terminal. The first capacitor has a first terminal coupled to the first terminal of the first inductor, and a second terminal. The second inductor has a first terminal coupled to the second terminal of the first capacitor, and a second terminal coupled to ground. The second capacitor has a first terminal coupled to the first terminal of the first capacitor, and a second terminal. The third capacitor has a first terminal coupled to the second terminal of the second capacitor, and a second terminal. The third inductor has a first terminal coupled to the first terminal of the second capacitor, and a second terminal coupled to the second terminal of the second capacitor.

Abstract: An integrated passive device with electrostatic discharge protection mechanism includes an antenna terminal for receiving and transmitting a wireless signals, a first frequency terminal for receiving and transmitting a signal with a first frequency, a first filtering circuit for filtering the wireless signal, and an electrostatic discharge protection element for conducting static electricity to ground. The first filtering circuit includes a first filtering element with a first end electrically connected to the antenna terminal, a second filtering element with a first end electrically connected to a second end of the first filtering element and a second end electrically connected to the first frequency terminal, and a third filtering element with a first end electrically connected to the second end of the first filtering element and a second end electrically connected to ground. The electrostatic discharge protection element is coupled between the second end of the first filtering element and ground.

Abstract: An antenna module in provided. The antenna module includes a metal housing, a radiator and a feed conductor. The metal housing includes a housing surface and a through hole. The radiator surrounds the metal housing. The feed conductor connects the radiator to an inner circuit inside the metal housing via the through hole.