在设计聚光太阳能热发电系统时，有必要分析聚光装置的聚光比。线性菲涅耳聚光反射装置是对连续抛物面聚光镜的一种离散化近似，该聚光装置中每一行反射镜面均实时跟踪太阳，将太阳入射光反射至固定位置的线性吸热器上，故每一镜元在吸热器上形成的反射光带宽度均时刻变化，这使系统聚光比分析变得非常复杂。利用二维光学分析，得到线性菲涅耳反射装置任一镜元的剖面角、跟踪倾角、单个镜元在吸热器平面上的光带宽度计算公式；得到线性菲涅耳聚光反射装置的几何聚光比公式并分析几何聚光比随镜元个数与相对距离的变化趋势。在分析系统聚光比的基础上，对该类系统镜场的宽度及塔高进行优化。最后给出考虑日轮张角情况下的几何聚光比变化。

It is necessary to analyze the concentration ratio for the design of concentrating solar thermal power system. Linear Fresnel reflector (LFR) can be treated as a smooth linear optical reflector that is broken into segments. Every mirror segment or row of this kind of concentrator needs to track the sun in real time and reflects the sunlight to a fixed linear receiver. Therefore, the bandwidth on the absorber illuminated by every mirror row varies continuously, which makes the analysis of concentration ratio very complex. Firstly, the formulae for the projected angles of incident and reflected solar rays, the tracking inclination angle and the bandwidth illuminated on the flat plane absorber are obtained by a two-dimensional optic analysis. Secondly, the expressions of geometric concentration ratio of LFR are derived and the dependence of ideal geometric concentration ratio on number of mirror slats and relative distance is analyzed. And then, optimization of mirror field width and tower height is analyzed. Finally, the effect of angular size of the sun′s disc on geometric concentration ratio is illuminated.