I did some digging of my own and managed to find the recommended footprint for-
But I cannot find the land pattern drawing for HMC3587. Could someone please help me out with this one?
I've inquired about this internally. While we do not a document for the HMC3587, there is an application note which provides guidelines for LFCSP packages which can be applied to the HMC3587.
Let me know if you need any more information.
Also note that for most devices, the gerber files for the eval board design are available on analog.com. Go to the product page, click on Evaluation Kits and look for resources. You can view the design files with a free viewer such as View Mate (https://www.pentalogix.com/t/software-products/viewmate).