I’m not entirely sure if this is satire, but in case it isn’t, lets explain how this stuff works.
Let’s start with the basics: What even is SAR?
It stands for Specific Absorption Rate, which is a measure for the absorbed radiation, converted to heat, in a human-like tissue sample.
This is only ever really relevant in a situation where the transmitter is very close to the tissue, because the potential for heat transfer decreases drastically with distance.
This would mean, an external stub-antenna, as common in early GSM phones and earlier analog mobiles, which increases the distance to the head by about 20 mm compared to an internal antenna, could improve the situation.
However, in reality this is not the case.
Modern 3G and 4G phones have very little power budget, and use relatively high frequencies with poor penetration.
A well designed phone needs to make sure, that said power is radiated in a way that causes least possible attenuation to work well; for a phone with internal antennas this means, a design will need to avoid radiating towards the head.
Not only because the head attenuates the signal (it does), but mainly because modern phones have a huge display and very little free space on the head-facing side, which usually has a metal shield, and a large PCB behind it.
This causes far larger attenuation than the head itself (which would only absorb a small amount of the radiated energy, while the displays metal shield will reflect a very large portion).
Because of this, most phone designs of the last decade tended to use the most obvious solution: place the antennas on the top backside of the device, where neither device, nor head, nor hand are in the way.
This causes them to radiate the vast majority of its power away from the head.
Since the antenna designs can typically achieve very little directionality, this is also caused by the displays shield, which reflects radiation away from the head.
Stub-antennas on the other hand have no such limitations - they radiate in a near isometric pattern, or to make it more understandable in a donut-shape around the antenna.
In turn this means, that even though the antenna now has a little more distance, it will actually radiate a larger portion of its power towards the head, since no reflector is in the way, and the radiation pattern is even less directional.
So a well done antenna internal antenna design will actually produce lower absorption in the head tissue (which may or may not be reflected in SAR measurements, depending on how they are done).
Stub antennas have in fact the advantage of less interference and tend to produce a more reliable connection, since omnidirectionality is what you want to have in a mobile device.
So why does nobody do it anymore?
First, it is just impractical. Such antennas make phones larger, customers much less likely to buy them, and are either bulky or get damaged easily.
Mainly however, it is, because we no longer have just one antenna in the phone.
We now need a least 2 antennas for LTE, and 1 or 2 for WiFi and Bluetooth.
Doing this as a stub antenna would make the phone look about like a walky-talky with a at least 50 mm tall plastic cover housing the 2-4 antennas.
So what does this mean?
Stub-antennas are more optimal for reception.
They are less optimal for SAR.
They are far less optimal in practicality.
They are more expensive, less robust, and consumers hate them.
