Every once in a while I get one of those "How could I forget that?" moments. I got one a few days ago when I remembered that RF design implemented in integrated circuits is not the same as that implemented in Printed Circuit Boards (PCBs). The cause was the joint announcement by Mentor Graphics and Agilent that they had developed a new integrated design environment for engineers doing RF design on PCB.
(See Mentor Graphics and Agilent Technologies aim to streamline RF PCB development
Cadence, of course is the reason I should have remembered all along. Virtuoso is the graphical environment for IC designers that are Cadence's customers, and they use Spectre, GoldenGate (also from Agilent) or any other RF simulator that is integrated in the Virtuoso Multi-Mode Simulation environment. But for those customers that are designing PCBs, the environment is Allegro. From there they have the choice of a few simulators, including Agilent's ADS, but the simulation environment is not as tightly coupled to Allegro as in the case of the IC design system.
Cadence introduced RF simulation capabilities for PCB design in June of last year, in response to several requests coming from Far East customers, most of them in China.
Just to complete the picture, Eldo RF is the Mentor simulator to use for IC design, while the company has no proprietary RF simulator for PCB design. According to John Isaac, a European customer asked Mentor to provide the RF simulation capability in their PCB design tool two years ago. It has taken this long to find a partner (although I suspect the customer already used ADS), negotiate a deal, and develop the required software. The result is that a designer can enter a circuit in the Mentor environment, simulate it in the Agilent ADS environment, cross probe and debug in either environments, and end up with a verified circuit in the Mentor environment ready to be integrated with the digital portion of the PCB.
I am sure that a few of you are now asking what took so long. After all one only needs common libraries and a package that supports dynamic linking between the two tools. Well it is a bit more complicated than that. You need to pay attention to the semantics of the interface and Mr. Isaac says that one of the weaknesses of prior Mentor PCB offerings was that "we did not understand RF". So one has to factor in the time required to gain the understanding necessary to learn how ADS speaks RF and translate it into as common a language as possible for both Board Station and Expedition tools. Considering that the null project takes nine months, two years is not too bad.