Keysight Technologies (Agilent HP) Switches

Keysight's electromechanical switch offering separates small coaxial microwave relays from modular switch/relay products for data-acquisition and ATE. Coaxial relay parts are identified by their pole/throw count and whether the unused port is terminated: examples include SPDT (single-pole, double-throw) units and multi-throw parts such as SP4T and SP6T. Multi-channel and general-purpose relay modules plug into switch/DAQ mainframes or rack instruments. For example, the 34903A is a 20-channel SPDT latching relay module designed for the 34970A and 34972A Data Acquisition/Switch Units, while the 3488A is a five-slot HP‑IB switch/control mainframe that can host multiple module types.

Terminated vs unterminated: Terminated switches route the unused port to an internal 50 Ω load; several terminated parts specify a 1 W CW internal termination power rating (example: the 87104C). Unterminated switches keep both RF ports available and typically prioritize lower insertion loss and higher peak power handling (example: the 8761B lists higher average and peak input power ratings in its standard configuration).

Frequency and RF performance: Frequency ratings and insertion loss vary by model. Examples: the 87104C is a terminated SP4T rated to DC–26.5 GHz with RF repeatability of 0.03 dB over a guaranteed 5,000,000 cycle life; the 87106B is an SP6T rated to DC–20 GHz with insertion-loss repeatability of 0.03 dB (up to 5 million cycles). The N1810UL and N1810TL product variants extend the family concept into higher microwave bands: the N1810UL offers options up to DC–50 GHz, while the N1810TL lists frequency options up to DC–67 GHz (option dependent).

Frequency target narrows the choices first. For applications above 20 GHz consider models with stated frequency ratings in that band (for example N1810UL options to 50 GHz or N1810TL options to 67 GHz). For automated test systems operating to 26.5 GHz, SP4T and SP3T terminated parts such as 87104C (DC–26.5 GHz) and 8766K (DC–26.5 GHz SP3T) are logical candidates.

Power handling and termination matter for hot-switching and bypass functions. Parts such as the 87106B specify RF power handling for hot switching (2 W CW) and peak pulses; others, like the 8763B bypass/transfer switch, provide low insertion loss and >90 dB isolation useful for transfer/bypass applications up to 18 GHz. Lifecycle and repeatability are important when switching is frequent: several latching models guarantee a minimum of 5,000,000 cycles and specify RF repeatability (0.03 dB maximum on some parts), which is relevant for production ATE where long-term repeatability is required.

Control and mounting options vary: many coaxial relay modules offer solder terminals, ribbon-cable, or D‑sub interfaces and selectable coil voltages (common nominal options are 5 V, 15 V or 24 V DC). Mainframes and controllers accept plug-in modules or drive external relays — for example, the 11713A provides GPIB control and an integral 24 Vdc supply to drive up to ten relays, while the 3488A is an HP‑IB mainframe with five module slots and configuration memory. When integrating, verify connector style (several coaxial units use SMA female) and the control interface required for your test system.