This paper presents the design and simulation of an RF prototype that can provide dynamic carrier aggregation (CA) in future cognitive heterogeneous cellular networks including also access to heterogeneous technologies. To this end, the proposed RF prototype can support heterogeneous multi-band CA scenarios with up to 3-band CA including unlicensed bands. Among other features, cognitive radio capabilities are incorporated to this prototype like spectrum sensing using energy detectors and dynamic CA using switches among the RF chains. The proposed architecture is evaluated in this paper highlighting useful insights of the proposed design. Our future work is to develop the proposed architecture using particular hardware components as an implementation within the framework of SOLDER FP7 project.