This paper presents an experimental demonstration of digital pre-distortion (DPD) on E-band power amplifiers (PA) with GHz channel bandwidth. An empirical optimization approach is used to quickly build up the look-up table of DPD coefficients, instead of the conventional behavior modeling technique. The digital pre-distorter is implemented by a simple 5th order memoryless polynomial function. The DAC sampling rate is 4.8 GSps. Based on our approach and system setup, the result shows DPD can push 2 to 3 dB more output power at the same in-band distortion level, which is equivalent to 58% to 100% efficiency improvement.