Small Circuit Area Research Articles

Microwave I-Q vector modulator using a simple technique for compensation of FET parasitics

The analysis and design of an improved technique for the realization of vector modulators using analog reflection-type circuits are presented. The analysis focuses on the detrimental effect that the parasitic elements of the FET variable-resistance elements have on the 360/spl deg/ phase and amplitude control. It is shown that a simple circuit technique can be used to compensate for the parasitic effects and achieve a near-ideal constellation. Compared with the balanced structure, the proposed technique leads to a much smaller circuit area and does not require additional complementary control signals. This makes it better suited to commercial wireless applications where low cost is paramount. Simulation and experimental results for an L-band prototype are presented.

Generic LR fuzzy cells for fuzzy hardware synthesis

A novel primitive cell structure for high-performance hardware realization of fuzzy computations is proposed in this paper. Such a cell structure is called generic LR fuzzy cell because it is an integral unit that encapsulates an LR fuzzy set and a basic fuzzy operation such as implication or arithmetic operation. Based on the proposed cell structure, we can develop two major kinds of fuzzy cell-LR fuzzy implication cell and LR fuzzy arithmetic cell-for the systematic synthesis of fuzzy application specific integrated circuits (ASICs) or general purposed fuzzy processors. The fuzzy systems synthesized with LR fuzzy cells possess the characteristics of decentralized knowledge manipulations and massively parallel inference. The system expandability and reconfigurability are also warrantable. This paper emphasizes on the design and application of fuzzy implication cell. The LR fuzzy implication cell is implemented with analog current mode technology. By this technology, an implication cell has the characteristics including small circuit area, high performance, low-power dissipation, etc. Moreover, the implication cell manipulates continuous data so that the realization of a pure fuzzy system is possible. In this paper, the key circuit characteristics of fuzzy implication cell are evaluated in details and there are two cases-fuzzy knowledge system and fuzzy mean filter-implemented to confirm the effectiveness and efficiency of fuzzy hardware synthesis by the LR fuzzy cells.

Multilayer MMIC broad-side coupler with a symmetric structure

A multilayer monolithic microwave integrated circuit (MMIC) broad-side coupler that has a symmetric structure has been fabricated and demonstrated. To enable the coupler area to be reduced, the width of the coupled lines in the fabricated coupler is made as narrow as 15 μm by using a meander-like configuration. The coupled lines are 2.28-mm long and effectively laid out in a small area of 0.9 mm×0.12 mm. The device works well and has good performance at frequencies between 10-17.5 GHz, with coupling loss of 4.2/spl plusmn/0.4 dB and return loss of better than 20 dB. This newly developed coupler offers advantages of simple symmetric design and small circuit area.