RF signal generators available from Saelig put out analog, vector signals over 9 kHz - 4 GHz/6 GHz with 0.001-Hz frequency-setting resolution
RF Signal Generator - SG380 Series
TWINTEX SG-150 RF Signal Generator, 150 MHz -Alibaba.com
DIY RF Signal Generator - YouTube
RF Generators Archives | Diros Technology
0.5MHZ‑470MHZ Signal Generator,RF Signal Generator Audio Modulation Signal Source Conditioning Radio 800Hz,Analog Sub-Tone Digital Sub-Tone,for Aviation/Wireless Communication/Manufacturing: Amazon.com: Industrial & Scientific
RF Plasma Generators | Plasma Power Generators | Advanced Energy