MECA Directional Couplers for Wireless Band Applications.MECA’s 715 series directional couplers feature unique air-line construction that provides for the lowest possible insertion loss (less than 0.1 dB) high directivity (30 dB typ) and exceptional VSWR (1.10:1 typ) across the 0.800 - 2.200 GHz and 2.000 - 4.200 GHz bands.