What we really need
Uusally when antigravity devices come up for discussion, the objection is on the grounds of conservation of energy. The classic example is H. G. Wells' Cavorite, which, if it existed, would enable you to get an infinite supply of energy. Covorite was a substance which shielded against gravity...so you could cover a mass, let it float up, uncover and let it fall, getting free energy, and repeating the cycle indefinitely. While this would be nice, it would definitely not be conserving energy, and since this principle is well established, it would appear to be very unlikley that a substance like Cavorite could actually exist.
That does not necessarily preclude the existance of something that would fit the description of antigravity, yet would also comply with the principle of conservation of energy. So what would be the characteristics of such a device? Well, experience tells us we will not get something for nothing, so it is probably going to cost us some energy to keep the device running. So while it is running, we would expect such a device to somehow overcome the local gravitational attraction, so that instead of falling it remains where it is as long as it is working. Now, staying in one place is not all that useful, so we would also like to be able to have the device raise itself, and lower itself, under control. When it raises itself it will have gained gravitational potential energy, so we must expect to have to put in an equivalent amount of energy, plus a bit more since few things are 100% efficient. Conversely when it lowers itself energy will become available, and we may even with luck be able to recover some of it.
So far we have just described a helicopter, an aeroplane, or even a lift for that matter. So the next thing is that our hypothetical antigravity machine must be able to accomplish all of this without a physical connection to the ground (or any other fixed object), without using reaction mass, and without requiring an atmosphere around it. you cdan accomplish things a bit like this with a good strong magnetic or electrostatic field, but what we would really like is to be able to do this a long way from any other fixed object, so that for instance we could start off on the ground, rise straight up into the air, and reach earth orbit. The actual orbit would also require us to accelerate sideways of course, but we would naturally be happy to feed in the energy needed to do this.
The interesting thing is that if you work out the energy to do this, for say a useful size of space capsule, it is not all that high. If the actual cost of the energy were the only barrier to space flight, we would already have commerce around the solar system. Sadly, we don't know how to make such an antigravity device, and I see no particular reason to beleive that the device referred to in the article represents any sort of step towards this. Ity would be nice, but just because some sort of device would be nice does not mean that it is actually possible to build one.