This research present a design of a higher  gain (66.38dB) for PHEMT LNA  using an inductive drain feedback technique for wireless application at 5.8GHz. The amplifier it is implemented using PHEMT FHX76LP transistor devices.  The designed circuit is simulated with  Ansoft Designer SV.  The LNA was designed using  T-network as a matching technique was used at the input and output terminal,  inductive generation to the source and an inductive drain feedback. The  low noise amplifier (LNA) using lumped-component provides a noise figure 0.64 dB and a gain (S₂₁) of 68.94 dB. The output reflection (S₂₂), input reflection (S₁₁) and return loss (S₁₂) are -17.37 dB, -15.77 dB and -88.39 dB respectively. The measurement shows the  stability was at  4.54 and 3-dB bandwidth of 1.72 GHz. While, the  low noise amplifier (LNA) using  Murata manufactured component provides a noise figure 0.60 dB and a gain (S₂₁) of 66.38 dB. The output reflection (S₂₂), input reflection (S₁₁) and return loss (S₁₂) are -13.88 dB, -12.41 dB and -89.90 dB respectively. The measurement shows the  stability was at  6.81 and 3-dB bandwidth of 1.70 GHz. The input sensitivity more than -80 dBm  exceeded the standards required by IEEE 802.16.

This paper presents the design of a direct conversion RF receiver and its sensitivity performance analysis for WLAN point to point communication at 5.8 GHz band based on IEEE 802.11a standard. The direct conversion RF receiver has been designed with proper selection of RF sub-components such as low noise amplifier (LNA), RF amplifier, power divider and filter. The selected RF sub-components of the RF receiver have been further analyzed for sensitivity performance in simulation. It is shown that the system noise figure influences RF receiver's sensitivity. It is contributed by the first stage of RF subcomponent which is LNA in the RF front-end system. As results, the 1.31 dB system noise figure has been selected in order to get the best sensitivity for direct conversion RF receiver which is -74 dBm and dynamic range of 47 dB at 54 Mbps. Besides, this direct conversion RF receiver has met sensitivity specification for all data rates based on the IEEE 802.11a standard.

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