Iframe card, compound url does not work

Configuration Frontend
1

Hi all,

I wanted to show a google maps card within an iframe. This works fine, but now I wanted to use the device.tracker parameters as an variable. It works in markdown-card but not in the iframe-card. Does anyone know, how this can be implemented?

type: iframe
url: >-
  https://maps.google.com/?t=k&q={{state_attr("device_tracker.cupra_born_tracker","latitude")}},{{state_attr("device_tracker.cupra_born_tracker","longitude")}}&output=embed
aspect_ratio: 50%
title: Car