Microwave Beam Gun...

If you wear clothing and footwear that contains or is covered with a very light-weight metal mesh and have a metal mesh hood that you can easily see through, the microwaves will be converted to electric current that can be dissipated by a grounding device, perhaps a metal plate on the sole of each shoe. At least that's what I've gathered from my limited online research. In other words, it is easily blocked with protective gear.

Infrasound guns, the infamous "Crap Canon," are a thornier problem. Blocking infrasound requires a mechanism that converts the sound waves to heat. One approach is to form a barrier of steel bells that will ring to the ultra-low frequencies. These bells are sandwiched together with other bells by means of a very viscous middle layer. (I imagine something like automotive gasquet sealant.) When the two bells respond to the infrasound vibration they are at odds with each other and work the sticky material rapidly, causing it to heat up, thereby greatly dampening the wave strength.

My guess is that the crap cannon riot vehicles are equipped with just this type of acoustic armor, perhaps a couple layers thick and water cooled. It must be pretty costly but a room could be outfitted with this kind of protection.

Fearmongering is really starting to disgust me. We've seen horrific weapons of war in the past century like aerial bombing, napalm, mustard gases, nerve gases, cluster bombs and nukes, that all make these high tech toys look as harmful as a can of pepper spray by comparison.

These microwave weapons and taser devices are only scary because of the context in which they are intended to be used--police actions on the street. In a war, they amount to nothing on the carnage scale.

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The microwave 'beam' is EM energy. Standing behind a grounded metal railing or chain link fence will dissipate much of the harmful effects. Also know this weapon is a line-of-sight device. If you hide behind a building or a friend they can't get to you. The weapon also requires some time to do it's job. A moving target will absorb less energy.

You could also wear a suit of popcorn or a vest full of coffee and make it a win-win.

Also consider shooting back. I don't think a microwave transmitter can out gun a gun.

have rubber on one side and aluminum on another. Any cop flashing a microwave or laser against such a surface is unlikely to want to do it again.

BTW, for night riots, answer a laser targeting device with mirrors and laser pointers. The low power red ones will not do permanent damage, but the green ones and high power red will burn out a sniper's eyes.