A 10 GHz microwave bridge measurement system has been developed to automatically measure the electromagnetic field parameters transmitted through a dielectric material. These parameters are used to calculate the complex dielectric constant with the free-space transmission technique. The system is used to measure the field parameters transmitted through dimension lumber and a correlation is made with two strength determining factors of lumber: specific gravity and moisture content. Hemlock and Douglas Fir wood samples were tested and a grading technique was implemented. The system is capable of estimating the specific gravity to ±0.05 accuracy and the moisture content to ±3.0% accuracy. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate