def fetch_sensor_pattern(pattern, client, log):
    """Fetch sensor pattern for each antenna. 
       
       Args:
           pattern (str): per-antenna sensor name with antenna fields
                          replaced with braces.
           client (obj): KATPortalClient object.
           log: logger

       Returns:
           sensor_details (dict): sensor results including value and timestamp
                                  of last change in value.
           None if no sensor results obtainable. 
    """
    try:
        sensor_details = yield client.sensor_values(pattern, include_value_ts=True)
        return(sensor_details)
    except Exception as e:
        log.error(e)
        return(None)