광대역 RF 수신기 설계에 관한 연구

Abstract

A wideband digital RF receiver front-end employing a discrete-time (DT) filter is presented for application to m-WiMAX (WiBro).By employing a sampling mixer and a DT filter, the receiver operates in the charge domain.In addition to the flexibility of the DT filter,the new non-decimation finite impulse response (NDF) filter can be cascaded to a conventional finite impulse response (FIR) filter without the decimation effect.Thus, we can easily increase the order of the $sinc^{n}$ function-type filtering response and the signal processing bandwidth.The FIR filter is also modified to reduce the noise and the number of required clock signal.Because of the new filter configuration, clock signals can be shared by the FIR filter and NDF filter and the clock generator circuit can be simplified.The designed receiver front-end is implemented using an IBM 0.13-$\mu$m RF CMOS process.The fabricated chip satisfies the m-WiMAX specification of an 8.75 MHz channel bandwidth and the total system current dissipation is 26.63 mA from a 1.5-V supply voltage.Not only the wide signal channel bandwidth but also the wide total frequency range covered by a receiver is an important issue with next-generation wireless communication.One of the most common broadband RF receivers is a TV tuner receiver front-end.A silicon IC-type TV tuner to process many TV broadcasting standards at once has been actively researched.Silicon tuner features smaller size, much cheaper cost for manufacturing than can-type tuner, and no requirement for extra tuning after fabrication.Mobile TV tuner receiver covers very wide frequency range over 54MHz - 870MHz, and there are many channels in the band and the spacings between the channels are very small.The LO signal applied to a mixer is not pure sinusoid, but a square wave effectively. The square wave has not only the wanted f$_{RF}$ component but also odd-order harmonic frequency components.When the RF signal is down-converted by mixing with the LO signal, the interferer signals at the odd-order harmonic frequencies are also down-converted to baseband by mixing with the harmonic frequency component of the LO signal.These down-converted interferer signals degrades signal-to-noise ratio (SNR) as a noise.So we need high linearity and interferer rejection in a broadband RF receiver.To solve this issue, the proposed TV tuner receiver employs a broadband low noise amplifier (LNA) with simultaneous thermal noise, IM2 and IM3 distortion cancelation.Furthermore, to achieve good harmonic-rejection mixing, two-stage iterative weighting harmonic-rejection mixer structure is used.The designed TV tuner receiver covers the frequency range of mobile TV tuner and has good gain, noise figure and harmonic-rejection ratio (HRR).In addition to this, a broadband RF receiver can be realized by extension of clock generator frequency range.We did layout of the designed TV tuner receiver with Samsung 65nm RF CMOS Process and verified the performance by simulation.