Dynamic spectrum access based on cognitive radio systems is highly desired to satisfy the expanding wireless communication demand. However, cognitive radio is in need of a compact antenna that is capable of covering a large frequency range. In this paper, a novel reconfigurable broadband antenna is proposed, which is capable of a dynamic multiple channel access in the frequency range from 400 MHz to 4 GHz. The proposed antenna maintains the compact size so that it is suitable for mobile multiple-input-multiple-output (MIMO) applications. The antenna achieves a minimum −5 dB channel bandwidth of 33 MHz which is large enough for TV whitespace applications.