| Most emphases are placed on the linearization technology during studying the microwave power amplifier, the microwave power amplifier with Feedforward technology, which has an advanced performance, is widely used. Usually, afeedforward amplifier adopts double-loop linearization technology, which means that there are two Feedforwad loops in the circuit: an error signal extraction loop which is used to extract the distortion(error) signal, and an error elimination loop which is used to ensure that only the main signal components appear in the output. However, the double-loop design contains a great number of components and requires delay lines in the power amplifier which lead to a large amount of power consume and low efficiency of the transmitter. A new technique, Feedforward single loop linearization technology, is provided in this article. Different from Feedforward double loop linearization technology, it just adopts one feedforward loop to cancel the error signal, and use an error signal generator to replace the error signal extraction loop of the double loop design. By this way, the circuit is simplified, the sensitivity to temperature is reduced and the stability of system is improved.In this paper, the general principle of the feedforward single-loop power amplifier is elaborated, which prove that it is feasible. On the basis of this, the cancellation performance of loop and the efficiency of the system are studied. The result proved that the cancellation performance of cancellation loop is decided by the amplitude imbalance, phase imbalance and delay mismatch.A 869-894MHz power amplifier using single loop linearization technology is designed. The results are given for a series of two-tone intermodulation distortion measurements. It is shown that an 18dB improvement in the intermodulation margin can be achieved.Additionally, the rule that the temperature affects the performance of system is analyzed, an effect way is provided for temperature compensation.
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