Hello andyd
As I installed it in an old Asbach car with a simple aerial without amplifier, I was able to use a passive analogue DAB adapter "inherited" from others without having to fit a windscreen aerial. OK, I know my feedback is not very helpful, but I'm sure you can find such analogue DAB+ adapters on sale if you have a car without an electronic antenna.
Greetings Aladin

I personally bought this one which works very well and is easy to install.
Pioneer DAB Disc Antenna