yes it is this one its beam angle is 40 degree , which i tested it cover the 40 degree at a distance of two feet or 70 cm.
in my project there is pre defined arena which is made up of wood now how can i cover the boundaries with metal foil
yes i can replace my obstacles with the metals ones rather than paper.
Multiple sensors at different angles would probably work best. The problem is that the object needs to be a certain width and basically facing the sensor for sound to bounch off it. If the object is pointed, sound won't bounce off to get an echo. However, if you have two angles, it raises the odds that you will find the object.
Most ping libraries don't work well when using multiple sensors due to their 1 second delay at times. However, my NewPing is specifically designed to be fast enough to use multple sensors. NewPing Library
I also have a two sensor example sketch
that you can use as a basis for your code. With the NewPing library, you could ping both sensors easily around 10 times per second (20 pings) while still doing other things like controlling your bot.