65

3

Thin-Film Directional Couplers

DB0805 3dB 90° Test Jigs

GENERAL DESCRIPTION

These jigs are designed for testing the DB0805 3dB 90°

Couplers using a Vector Network Analyzer.

They consist of a dielectric substrate, having 50

Ω microstrips

as conducting lines and a bottom ground plane located at a

distance of 0.254mm from the microstrips.

The substrate used is Neltec’s NH9338ST0254C1BC.

The connectors are SMA type (female), ‘Johnson Components

Inc.’ Product P/N: 142-0701-841.

Both a measurement jig and a calibration jig are provided.

The calibration jig is designed for a full 2-port calibration, and

consists of an open line, short line and through line. LOAD

calibration can be done by a 50

Ω SMA termination.

When measuring a component, it can be either soldered or

pressed using a non-metallic stick until all four ports touch

the appropriate pads. Set the VNA to the relevant frequency

band. Connect the VNA using a 10dB attenuator on the jig

terminal connected to port 2. Follow the VNA’s instruction

calibration in the required bandwidths.

Input (Coupler)

➜ Connector 1 (Jig)

Output 1 (Coupler)

➜ Connector 3 (Jig)

50

Ω (Coupler)

➜ Connector 2 (Jig)

Output 2 (Coupler)

➜ Connector 4 (Jig)

Connector 1 (Jig)

➜ Port 1 (VNA) Connector 3 (Jig) ➜ Port 2 (VNA)

Connector 2 (Jig)

➜ 50Ω

Connector 4 (Jig)

➜ 50Ω

Connector 1 (Jig)

➜ Port 1 (VNA) Connector 3 (Jig) ➜ 50Ω

Connector 2 (Jig)

➜ 50Ω

Connector 4 (Jig)

➜ Port 2 (VNA)

Connector 1 (Jig)

➜ 50Ω

Connector 3 (Jig)

➜ Port 1 (VNA)

Connector 2 (Jig)

➜ 50Ω

Connector 4 (Jig)

➜ Port 2 (VNA)

MEASUREMENT PROCEDURE

Measurement Jig

Connector 1

Connector 2

Connector 4

Connector 3

Calibration Jig

Short Line

to GND

Load &

Through

Load &

Through

Connector

Johnson

P/N 142-0701-841

Open

Line