Inventing new characters seems to have been still practiced quite commonly through the 20th century.
For instance, the character “熵” means entropy, and was coined by a Chinese physicist Húgāngfù in 1923. In Japan, we simply use the transliteration “エントロピー(pronounced entoropi-)” for the word, but I think it’s way cooler to write with one character.
A more recent one will be a character for “virtual” as shown below, which was proposed by Tachi Susumu in 2005, a notable engineer who’s famous for his contribution to virtual reality.
Virtual reality in Japanese is translated as 仮想現実(imaginary reality), and in Chinese it’s 虛擬實境(pseudo reality) both having the meaning of “imaginary” or “fake”. However, if you look up the dictionary of “virtual”, you can see the following definition:
1. being such in essence or effect though not formally recognized or admitted
As you can see from the definition, the conventional translation doesn’t convey the same meaning. The proposed character consists of “忄”(heart) + “實”(real/essence), meaning that “it appears as being real to your heart” or “the same as reality in your heart”, which is much closer to the original meaning of “virtual”, and would describe “virtual reality” in a much more accurate way.
(Image cited from original proposal, proposing the character in the form of an entry of a Sino-Japanese dictionary)
Same thing goes for the translation of “virtual short”. I’d say that translating “virtual short” into 仮想接地 (imaginary short) or 虛擬短絡 (pseudo short) could even be called an outright mistranslation. You can use the character in this case as well. Note for for non-engineers: “virtual short” is used when the two inputs of an op-amp appears to be at the same voltage due to the great amplitude gain. I digress.
So yes, there are characters being invented still today, but adding that to the current character set like Unicode is another problem. All the recent additions to the Unicode CJK character sets seem to come from old dictionaries or letters used by ethnic minorities like the Sawndip characters.