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HOME  >  ANSL R&D Times  >  No.38_1 (2004_04)  >  18.Wireless technologies for WT
ANSL R&D Times

18.Wireless technologies for WT

We developed analog devices to reduce drastically reduce the number of the components and to downsize the equipment. For example, up-converter and down-converter (Fig. 18), which require more than three circuits (mixer, multiplier, buffer amplifier, and so on) in each, are integrated into one-chip MMIC. This MMIC and PA are flip-chip mounted into a surface-mounted MMIC package (Fig. 19) that is also newly developed for the WIPAS.

The IF filters must have flat and low-ripple characteristics inside the pass band and steep attenuation outside the band, in order to obtain a large enough IRF, which is an important factor in designing high-density cells. We newly developed a Surface Acoustic Wave (SAW) filter that has those these characteristics as an IF filter.

Furthermore, an analog silicon IC was developed for the orthogonal modulator/demodulator to integrate the circuit. This silicon IC consists of a pair of a modulator and a demodulator pair with a composition of IF gain controllers.

Figure 17 Configuration of WT

Figure 17 Configuration of WT
Figure 18 Up and Down converters

Figure 18 Up and Down converters
Figure 19 Surface mounted MMIC package

Figure 19 Surface mounted MMIC package

 

The WT planar antenna (18 cm x 18 cm; 31.5 dBi) is constructed with an alternating-phase fed single-layer waveguide array to obtain high gain, the ability for mass-production, and a low-cost structure. Fig. 20 illustrates the WT planar antenna. This antenna consists of a slot plate and a corrugated base, and is a part of the WT housing for inner components such as MMICs, an IF module and an Application Specific IC (ASIC). This planar antenna is also a part of the WT cooling element. A slot plate and a corrugated base are simply tacked together with surrounding chokes and do not require mutual electrical contact. This characteristic contributes to reducing the cost and size of the WTs.

 

Figure 20 Configuration of planar antenna

 

Figure 20 Configuration of planar antenna