Hi,
I can help you with this project, i have experience on antenna design with CST in frequency bands as 433 MHz, 915 MHz, 2.4 GHz. Please share more details with me,
1. Frequency bands of operations and bandwidths (or technologies eg. WIFI, Bluetooth, sigfox...)
2. Available space for the antenna (superficial and volumetric dimensions if is possible)
3. A full description of the device in where it will be integrated, electrical circuit diagrams, 3d models....
I can help you to create a best specification for your device.
regards,
We can talk for fix a price for the project.