I know this is an elementary question.
I know that SMD design has the advantage of smaller board size but I dont know which design works better in higher frequencies.
It depends on your design but if I wanted use a design for high frequencies, I used through hole just for power/heating parts and used SMD for the rest because SMD design can reduce inductance and resistance of component parts .
Advantages of SMD:
2- Much higher component density (components per unit area) and many more connections per component.
3-Lower initial cost and time of setting up for production. Fewer holes need to be drilled.
4-Simpler and faster automated assembly.
5- Small errors in component placement are corrected automatically as the surface tension of molten solder pulls components into alignment with solder pads.
6-Components can be placed on both sides of the circuit board.
7-Lower resistance and inductance at the connection; consequently, fewer unwanted RF signal effects and better and more predictable high-frequency performance.
8-Better mechanical performance under shake and vibration conditions.
9-Many SMT parts cost less than equivalent through-hole parts.
10-Better EMC compatibility (lower radiated emissions) due to the smaller radiation loop area (because of the smaller package) and the smaller lead inductance.
Disadvantages of SMD:
1- Manual prototype assembly or component-level repair is more difficult
2-SMDs cannot be used directly with breadboards
3-SMDs' solder connections may be damaged by potting compounds going through thermal cycling.
4- SMT is unsuitable for large, high-power, or high-voltage parts, for example in power circuitry.
5-SMT is unsuitable as the sole attachment method for components that are subject to frequent mechanical stress