A 90 nm-CMOS IR-UWB BPSK Transmitter With Spectrum Tunability to Improve Peaceful UWB-Narrowband Coexistence
A 90 nm-CMOS IR-UWB BPSK Transmitter With Spectrum Tunability to Improve Peaceful UWB-Narrowband Coexistence
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DOI：
10.1109/tcsi.2013.2290849
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发表时间：
2014-01
期刊：
影响因子：
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通讯作者：
Sayed Vahid Mir-Moghtadaei;A. Fotowat-Ahmady;A. Z. Nezhad;W. Serdijn
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文献类型：
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作者：
Sayed Vahid Mir-Moghtadaei;A. Fotowat-Ahmady;A. Z. Nezhad;W. Serdijn
为了缓解冲激无线电超宽带(IR-UWB)系统与IEEE802.11.a无线局域网或其他窄带(NB)系统在90 nm-CMOS工艺下的共存问题，提出了一种新的超宽带(UWB)脉冲发生器，其覆盖范围为2.4~4.6 GHz，中心频率为5~5.6 GHz。UWB脉冲是基于对高斯脉冲的一阶导数进行频率上转换而产生的，这在频谱中产生了可调整的零点。仿真结果表明，采用该脉冲发生器可以显著降低UWB和WLAN系统之间的相互干扰。该发射机由一个低频信号发生器、一个LC振荡器和一个混频器组成，其输出利用匹配的片上变压器直接驱动天线。两个控制信号根据NB频率并考虑工艺、电源电压和温度(PVT)的变化来改变发射频谱的带宽和中心频率。在采用电流脉冲注入的LC振荡器中采用了快速启动电路，并与混频器一起进行占空比以降低功耗。版图后仿真结果表明，当零带宽为100 MHz时，零深度为23分贝。在脉冲频率为860MPulse/S、有源电路面积仅为0.18mm2的情况下，在1V电源下，能量/脉冲和归一化为输出电压幅度的能量/脉冲分别为14.4PJ/脉冲和35.7PJ/(PULSE-V)。
A new ultra wideband (UWB) pulse generator covering a -10 dB bandwidth of 2.4-4.6 GHz with a tunable center frequency of 5-5.6 GHz to mitigate coexistence issues of impulse radio UWB (IR-UWB) systems and IEEE802.11.a WLAN or other narrowband (NB) systems in 90 nm-CMOS technology is proposed. The UWB pulse is generated based on frequency up-conversion of the first derivative of the Gaussian pulse, which creates an adjustable null in the frequency spectrum. Simulation results show that employing the proposed pulse generator mitigates the mutual interference between UWB and WLAN systems, significantly. The proposed transmitter consists of a low frequency signal generator, an LC oscillator and a mixer, whose output directly drives the antenna using a matching on-chip transformer. Two control signals change the bandwidth and center frequency of the transmitted spectrum depending on the NB frequency and considering process, supply voltage and temperature (PVT) variations. A fast start-up circuit is used in the LC oscillator using current pulse injection and together with the mixer is duty cycled to reduce the power consumption. Post-layout simulation results show a null depth of 23 dB for a null bandwidth of 100 MHz. The energy/pulse and energy/pulse normalized to the output voltage amplitude are 14.4 pJ/pulse and 35.7 pJ/(pulse-V) from a 1-V supply for a pulse rate of 860 Mpulse/s with an active circuit area of only 0.18 mm2.