For example: Agilent E4440A or Anritsu 68369
Couplers
Keysight / Agilent 5086-7489
TBR Single Directional Test Port Coupler, 50 Ohm
Manufacturer: Keysight / Agilent
Keysight / Agilent 5086-7557
HM DUAL CTLR Test Port Directional Coupler Refurbished - 5086-6557
Manufacturer: Keysight / Agilent
Keysight / Agilent 5087-7007
HP Agilent Keysight 5087-7007 Test Port Coupler, 50 Ohm
Manufacturer: Keysight / Agilent
Narda 5292
1 to 18 GHz, APC-7 connectors.13dB High Directivity Directional Coupler
Manufacturer: Narda
MECA Electronics 722N-40-0.900
RF Dual Directional Coupler, .6 - 1.2 GHz, 40 dB, 500W
Manufacturer: MECA Electronics
Keysight / Agilent 767D
20 dB, 1.9-4.1 GHz, N(m/f/f/f) Dual Directional Coupler
Manufacturer: Keysight / Agilent
Amplifier Research DC3400A
10 kHz to 400 MHz, 200 Watt, Dual Directional Coupler
Manufacturer: Amplifier Research