Table 1.

The frequency shift Δf per unit gas concentration and the SR of the four SAW modes for different gases, at a fixed PIB layer thickness (0.8 µm).

gas	Δf/Δc0 (Hz/ppm)				SR (ppm)
	λ = 30 µm		λ = 10 µm		λ = 30 µm		λ = 10 µm
	Rm	Sm	Rm	Sm	Rm	Sm	Rm	Sm
CH2Cl2	−0.25	−0.21	−1.57	−3.52	−11.86	−14.48	−1.91	−0.85
CHCl3	−1.01	−0.83	−6.27	−14.07	−2.96	−3.61	−0.48	−0.21
CCl4	−2.53	−2.08	−15.69	−35.17	−1.19	−1.44	−0.19	−0.09
C2Cl4	−3.28	−2.70	−20.37	−45.63	−0.91	−1.11	−0.15	−0.07
C2HCl3	−4.19	−3.45	−26.00	−58.24	−0.72	−0.87	−0.12	−0.05