A 2.6 GHz/5.2 GHz CMOS voltage-controlled oscillator

New wireless local area network (WLAN) standards have recently emerged in the 5 GHz band. For example, high performance radio LAN (HIPERLAN) is a European standard operating at 5.2 GHz with Gaussian minimum shift keying (GMSK) modulation and a 23 MHz channel bandwidth. The voltage-controlled oscillator reported here is to be used in a HIPERLAN transceiver. Here, the receiver employs two downconversion steps, each with a 2.6 GHz local oscillator (LO) frequency, translating the RF spectrum to dc. The second downconversion thus requires the quadrature phases of the LO. The transmitter performs modulation by first placing the VCO in a synthesizer loop and subsequently opening the loop and applying the Gaussian-shaped baseband data to the VCO to perform GMSK modulation.