To begin, it is important to understand the definition of wavelength. Wavelength is defined as the speed of light over frequency, with that, as frequency increases, wavelength decreases. For example, if one had 3 GHz, and the wavelength is 10 cm. At 900 MHz the wavelength is 33 cm. So, as the frequency is decreasing, the wavelength is increasing. Why is this important? To have a well performing antenna, the physical dimensions of the antenna are going to have to be in a perishable factor of a wavelength, typically a quarter wave or larger. Therefore, one needs to design enough space and ground plain length to allow for an efficient antenna. Frequency has a direct impact on the device size and the antenna performance.