Driving a MA40S4 transducer

Hi, so I tried driving a MA40S4 transducer with a max232. This chip charge pumps capacitors and manages to create +12V - 12 from a 5V supply. The HC-sr04 ultrasonic sensor uses them. But my MA40S4 has a angle range of 80 degree, so when I drive it with the max232 I have a really lower range then when I drive a 30 degree Hc-sr04 transducer. Probably because the max232 does not supply enough current and the datasheet of the MA40S4 ask for +/-20v.
What kind of of circuit could I use to create a +20 -20V for the MA40S4 ? (using a batterie, anny kind, lipo etc)

Thanks

a chip like is limited to 30mA. Since the ultrasonic pulse is quick will it be able to deliver more current but for a shorter amount of time ?