awk parameter substitution fails

I am on Ubuntu 20.04 Mate Desktop environment.

I encounter a strange failure when I attempt to pass the date string to regex query in the following line :

  date="2020-12-11"  cat /var/log/dpkg.log | awk  ' / installed / && /$date/ {print $5}'

I tried different combinations as suggested in the forums:

  cat /var/log/dpkg.log | awk  ' / installed / && /${date}/ {print $5}'  cat /var/log/dpkg.log | awk  ' / installed / && "/$date/" {print $5}'

But they won't work.