Which of the following is a common RF connector type used in test equipment?

• A. SMA
• B. HDMI
• C. USB-C
• D. RJ-45

Answer: (A)

The main idea is choosing a connector that preserves signal quality at RF frequencies. RF test gear needs a connector with a well-defined impedance, secure mating, and low loss, so reflections and noise are minimized. SMA is designed for 50-ohm systems and uses a precise, compact threaded coupling that stays stable even with repeated connections. Its frequency range covers DC up into tens of gigahertz (commonly up to 18 GHz, with variants to 26.5 GHz), which is ideal for instruments like signal generators and spectrum analyzers. That combination—controlled impedance, reliable mechanical connection, and high-frequency performance—makes SMA the standard choice for RF test ports.

By contrast, HDMI, USB-C, and RJ-45 are general-purpose data or network connectors not designed to maintain RF impedance or provide the same shielding and stability at high frequencies, so they’re not used for typical RF test inputs/outputs.