In this paper, we study the design of dual-band concurrent low phase noise oscillator with negative resistance structure. First, for each frequency band, a single-band negative resistance oscillator is designed separately. A suitable dual-band matching circuit has been used to dual-band these two oscillators so that we can oscillate at both frequencies simultaneously at last oscillator operates concurrently at 2.4GHz and 5.2GHz frequencies separately. Synchronization improves the performance of the oscillator, increases the data transfer speed and reduces the dimensions of the oscillator and also the design method of the oscillator with negative resistance is a simple and low cost method in designing the oscillator. One of the challenges in designing an oscillator is the oscillator's phase noise, the oscillator should ideally have low phase noise. In this oscillator, the simulated phase noise values, at 10MHz offset for the frequencies of 2.4GHz and 5.2GHz are -137.28dBc/Hz and -140.388dBc/Hz,respectively and the amount of output powers are 3.991dBm and 4.583dBm.
