Gilbert upconversion mixers using single‐band/dual‐band LC current combiners

The 0.35‐μm SiGe BiCMOS high linearity Gilbert upconverters are demonstrated in this article by utilizing NMOS and PMOS transconductance amplifiers (TCAs), respectively. To improve the linearity of a Gilbert upconverter, the IF input TCA is replaced by a bias‐offset differential pair. A reactive LC current combiner is used as the load of the Gilbert mixer to double the output current. The upconverter with an NMOS TCA achieves the conversion gain of −4 dB, the OP 1dB of −11 dBm, and the OIP 3 of 5.5 dBm, whereas the other one with a PMOS TCA has the conversion gain, OP 1dB , and OIP 3 of −6 dB, −11 dBm, and 9.5 dBm, respectively. Furthermore, the LC current combiner can be extended to a dual‐band version. The 2.4/5.7 GHz dual‐band upconverter is also demonstrated in this work. The conversion gain at 2.4/5.7 GHz is −3/−3.5 dB with the OP 1dB of −15.5/−15 dBm and the OIP 3 of −2.5/−3 dBm, respectively. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1718–1722, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24433