A Ka‐band tunable LNA for MB‐OFDM application

AbstractIn this paper a novel tuneable LNA is presented. This LNA is designed with two separated structures which both of them utilize noise cancellation technique and some other approaches such as gain boosting and T‐transformer feedback. Each proposed LNA has two stages that the first stage is designed based on noise cancellation and the second stage uses common gate structure. The proposed LNA type (A) utilises the switched capacitance in the first stage to tune the centre frequency and a gain boosting in the second stage to increase the gain. The second proposed LNA type (B) has implemented the parallel networks to decrease the change in the gain values of the LNA in different channels. The T‐transformer approach is used in each parallel network to decrease the inductors value and improve the input matching. In the second stage, the negative feedback is also employed to control the bandwidth. The proposed LNA is simulated in ADS software with TSMC 130 nm CMOS technology and the layout is designed by Cadence. The LNA type (A) has 22.7 dB gain in 28.8 GHz and the noise figure of 2 dB. The IIP3 for this LNA is 0 dBm in 25.42 GHZ. For the LNA type (B), the gain and noise figure standard deviations are 0.25 and 0.057 respectively which shows minimum variations by frequency tuning. For this LNA, the maximum gain is 20.5 dB and the noise figure is 2 dB at 31.42 GHz. Finally the performances of the proposed LNAs have been compared with those of LNAs which have been recently published.