HMC311SC70 Faulty???


I have the HMC311SC70 RF Gain block on a number of custom made radar boards. These gain blocks are on the receiver path and RF generation path, both leading into a IQ mixer (HMC525LC4). Of recent, I discovered that about 3 of these boards will not pick up reflected signals- this I observed in ADC/data acquisition and confirmed using an oscilloscope.

To troubleshoot, I inject a -30dBm 5.9GHz signal into the RX path, and tried to measure output of all components on the path (LNA- RF Amp). Detected power at input port was about -45dBm, LNA output was about -23dBm and Gain block output (the HMC311) was about -44dBm.

On comparing with a 'working' board of same design, power detected at RX port was -45dBm, LNA output was -27dBm and Gain block output was -7dBm.

Could it then be that my RF amplifier is broken? Or am I missing something else? I am seeking advice/tips before I swap out the on board RF amps.

Looking forward to reading from you. Thanks in advance.