Abstract-In this paper, the most adequate architecture to implement dual frequency amplifiers is shown. Composite Right/Left Hand (CRLH) and Extended Composite Right/Left Hand (ECRLH) transmission lines are studied and evaluated to find the most suitable structure for dual band power amplifiers. As an example, the performance of a class CE amplifier, working in TETRA and GSM frequency bands, is compared with simulations and measurement, showing good agreement.
INTRODUCTIONThe increasing demand for wireless systems requires the use of higher frequency spectrum. Such high frequencies entail two major drawbacks: First, line transmission losses increase significantly. And second, solid state devices present power limitations at radio frequency (RF). Besides, when high RF power is demanded, there are some problems related with conventional system design and implementation, which can be overcome combining several RF devices to achieve the desired level. Another problem arises from the need of multifunction transponders to cope with several services, usually allocated at different frequencies, in the only terminal, being a well known example multiband or even GPS mobile phones. As a result of all these drawbacks, the development and use of multi-frequency highperformance power amplifiers is required. In this paper, TETRA Corresponding author: V. Gonzalez-Posadas (vgonzalz@diac.upm.es).
We propose a dielectric rod waveguide antenna (DRW) integrated with a photomixer as a THz emitter. This represents a different approach as opposed to the classical solution of a substrate lens. Main goals are an inexpensive alternative to substrate lenses, reduction of both reflections on the semiconductor-air interface and scattering of terahertz-generated power into the substrate. A radiation pattern measured at 137 GHz is shown as a proof-of-concept. In order to increase radiated power, the improvement of the rod antenna is discussed. Finally, as an application example, evanescent coupling of the DRW into a high index whispering gallery mode resonator is shown
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