Performances Analysis of LNA-Antenna Co-Design for UWB System

The co-design between an antenna and a low noise amplifier (LNA) is here addressed over an ultra wide frequency bandwidth: 3.1-5.1 GHz. The key idea of co-design is to relax the 50 Omega impedance matching constraint on both LNA and antenna thanks to joint conception in order to improve performances for a given power budget. On LNA side, the co-design benefits from removing the major part of the costly integrated passive elements serving as a matching circuit. The co-designed LNA benefits from a size, cost and noise figure reduction. The antenna input impedance has no more to fit constant and real impedance on the whole bandwidth. In the present case, this point is used to reduce dimensions. To quantify performance enhancement the followed strategy consists in comparing a classical 50 Omega and a co-designed active antenna design approach, with the same LNA architecture, the same power consumption and the same antenna kind.