Not much of a corporate structure really. The majority of patent companies are owned by private individuals, i.e. you and me as opposed to companies.
Basically you set the company as you would any other and get the patent in the name of that company. Then the trading company pays a royalty to the patent company for the use of the patented item. Provided all the necessary terms are met the patent company then discharges money by means of dividend to shareholders.
The dividends are usually exempt for tax, with the exception of being subject to Section 485D TCA 97.
If you are setting up a patent company I presume you have a tax consultant on board to ensure that everything will be allowable from a tax perspective?