BANDWIDTH ENHANCEMENT OF AN ANALOG FEEDBACK AMPLIFIER BY EMPLOYING A NEGATIVE GROUP DELAY CIRCUIT

We will demonstrate an alternative topology to greatly increase the operating bandwidth of an analog RF feedback power amplifler. A limited operating bandwidth due to the group delay mismatch of a feedback loop discouraged the use of an RF feedback technique in spite of its powerful linearization performance and great tolerance capability. By introducing a negative group delay circuit (NGDC) in the feedback loop, group delay match condition could be satisfled. With the fabricated 2-stage distributed element negative group delay circuit with a 30MHz of bandwidth and a i9ns of group delay for a wideband code division multiple access (WCDMA) downlink band, the proposed feedback amplifler with the proposed topology experimentally achieved an adjacent channel leakage ratio of i53:2dBc with a cancellation bandwidth of over 50MHz.