**3.4 MRAs with the same number of sensors and aperture might have different sensitivities**

Another important aspect that a designer must be aware of, is that there can exist many sensor configurations for a given aperture in the case of MRAs and MHAs. Each of these configurations may possess different radiation characteristics or sensitivity. For example, the first column in **Table 4** shows a few MRA configurations M1 – M4, each of which has seven sensors and is capable of offering an aperture of *L* ¼ 15. **Figure 4** shows their array patterns. It can be inferred visually from **Figure 4** and also reinforced from the remaining columns of **Table 4** that though the different MRA configurations provide the same aperture, they may not possess the same main beam and side lobe characteristics.

Hence, care must be exercised before choosing a given MRA configuration.


**Table 4.**

*Beamwidths and PSLs for different MRAs with same aperture and same number of sensors.*

**Figure 4.** *Array factors of MRAs M1-M4 mentioned in Table 4.*
