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In this paper two active MMIC mixers for RF front-end applications are described. A down-converter that converts an RF signal(fRF=10.45 GHz)into an IF signal(fIF=0.95 GHz)using an LO signal(fLO=9.5 GHz)and an up-converter that performs the opposite process have been fabricated. The down-converter is designed using the topology of a dual-gate pHEMT, while the up-converter is implemented in the form of a double balanced mixer using the topology of the Gilbert cell and the occupied areas are approximately0.78 mm2and3.86 mm2, respectively. Both mixers present conversion gain, very low input and output return losses, very good isolation between all of their ports and the required LO power is quite low, while the up-converter contains on chip, except for the dc-bias and matching sub-circuits, the required LO and RF baluns. Both circuits have been fabricated using the H-40 process of GEC-Marconi. Section 1 presents fundamentals on mixer theory and mixer design while in Section 2 the characteristics of H-40 process are described. In Section 3 and in Section 4 the designing, the simulated and the measured results of the down-converter and the up-converter are presented, respectively.

In this paper a MMIC QPSK modulator is described. The bit rate of the baseband signal is 155 Mbits/sec, while the frequency of the carrier isfLO=10 GHz. The modulation is performed directly at the RF band and therefore an IF stage is not necessary. The design contains all the necessary sub-circuits except for the demultiplexer and the low-pass filters, which are used so that the bandwidth of the binary waves can be reduced. The mixers that are contained in the circuit are not the typical Gilbert cells and as a result they occupy a much smaller area (half). The circuit needs no external LO coupler and no RF chocks. The F-20 process of GEC Marconi was used for designing the modulator. The occupied area is approximately12 mm2. Section 1 presents fundamentals on Quadriphase Shift Keying (QPSK), while in Section 2 the characteristics of the F-20 process are described. In the following Sections the sub-circuits, the complete circuit, and its simulated results are presented.

The Lab of Tomorrow project introduces innovation both in pedagogy and technology. It aims at developing tools that allow for as many links as possible between teaching of natural sciences and every day life. Since science deals with the study of nature and the world around us, teaching science cannot be separated from daily experiences that result from student's interaction with the physical phenomena. In the Lab of Tomorrow project the re-engineering of the school lab of tomorrow is proposed along with the development of a new learning scheme based on the production of computational tools and project material that allow high-school students to use their every day life environment as the field where they conduct sophisticated experiments.