Connection unit

A connection unit comprising:

• a ceramic substrate having a top surface and a first side surface that is transverse to the top surface;
• a first signal line on the top surface of the ceramic substrate;
• a first grounded conductor on the top surface of the ceramic substrate that is electrically insulated from and electromagnetically coupled to the first signal line;
• a first lead pin having a first end connected to an upper surface of the first signal line and a second end protruding beyond the first side surface of the ceramic substrate;
• a second lead pin having a first end connected to an upper surface of the first grounded conductor and a second end protruding beyond the first side surface of the ceramic substrate;
• a flexible substrate including
• a first insulating layer having first and second major surfaces that are opposite each other,
• a second grounded conductor on the second major surface of the insulating layer,
• a second signal line on the first major surface of the first insulating layer of the flexible substrate, wherein
• the flexible substrate is mounted on the first side surface of the ceramic substrate with the second grounded conductor in contact with the first side surface of the ceramic substrate,
• the first and second lead pins penetrate through the flexible substrate,
• the second signal line is connected to the second end of the first lead pin, and
• the second grounded conductor is connected to the second end of the second lead pin;
• a second insulating layer on the second grounded conductor;
• a third grounded conductor on the second insulating layer opposite the first insulating layer, including a bend, and extending onto and connected to the first grounded conductor, wherein the second insulating layer includes a first via through which the second grounded conductor and the third grounded conductor are connected to each other;
• a third insulating layer on the third grounded conductor opposite the first insulating layer, including a bend, and extending onto the third grounded conductor opposite the first grounded conductor;
• and
• a fourth grounded conductor on the third insulating layer opposite the third grounded conductor, wherein
• the third insulating layer includes a second via through which the third grounded conductor and the fourth grounded conductor are connected to each other, and
• the second via is located opposite the first grounded conductor, between the first lead pin and the second lead pin, and spaced from the first lead pin.