I mostly know about every sensor made and run many many tests on them
some for work but mostly for robot designs i ,might have well over 30 different types
ON sonars narrow detection is needed to mostly detect the corner of the 2 walls that meet for good navigation ,but also thin table legs or chair legs ,also doorways .
When a sonar transmitt a utrasonic pulse it sends like a cone shape.wider the cone shape wider the detection.
So there is 2 ways to do it,so far maxsonars sells smaller cone angles $30 each
Other way is easy with like SRF-04 types like EZB sells on the transmitt side you need to reduce the SIDE SLOPES or cone angle.
its fairly easy only need a tube that fits on the outside of the ultrasonic tranducer and in the inside place a foam tube smaller the ID smaller the cone
and length is about 1 1/2 inch long on the tube,can use cardboard type
on foam tube inside length is about 1 inch
try to match it to get a tight fit inside the cardboard tube
also best place to place them on robots is on each corner at 45 deg
and then have 2 facing forward like headlights with no cardboard tube or foard to pick up wide angle objects
latter on will give you info on IR sensors too