1830 IEICE TRANS. ELECTRON., VOL.E95–C, NO.11 NOVEMBER 2012 BRIEF PAPER A Proposal of High-Performance Samplers Based on Resonant Tunneling Diodes Koichi MAEZAWA †a) , Senior Member, Jie PAN † , Dongpo WU † , Student Members, and Masayuki MORI † , Nonmember SUMMARY A novel type of millimeter/submillimeter wave sampler based on resonant tunneling diodes (RTDs) was proposed, and its operation was confirmed by circuit simulation. It consists of an RTD pulse generator and an RTD detector. Owing to the fuse-like nonlinear I-V curve, highly sensitive sampling can be obtained. We also found that the effects of non- ideality in the I -V curve of the RTD can be corrected by sweeping the DC bias for the RTD detector. key words: sampler, pulsar, resonant tunneling diode 1. Introduction Recently, resonant tunneling diodes (RTDs) are gaining in- creasing attention again due to the increasing interest in THz wave technology. Ultra high frequency oscillations higher than 1 THz have already been demonstrated for RTD oscil- lators integrated with an antenna [1], [2]. RTD-based har- monic oscillators have also been reported to overcome sta- bility problems in RTD oscillators [3], [4]. Besides oscilla- tors, an ultrawideband amplifier [5], ultrashort pulse gener- ators [6]–[9], gyrators [10], and analog-to-digital convert- ers [11], [12] have been investigated during the last decades. Moreover, THz wave communications based on an RTD de- tector have been demonstrated most recently [13]. They re- ported the RTD-based detector has much high sensitivity compared to the conventional Schottky diode based detec- tors due to the strong nonlinearity. In this paper, we propose a high performance sampler based on the RTD-detector and the RTD-pulse generator. It has features of ultrawide band and high sensitivity. 2. Basic Operation of the Sampler Circuit In this paper, we propose a sampler circuit shown in Fig. 1, which consists of a simple RTD pulse generator [9] and an RTD detector. The RTD is biased in the low-voltage positive-resistance region (PDR) via low pass filters con- sisting of an inductor, a capacitor and a small resistor. The small resistors, the values of which are smaller than the ab- solute value of the negative differential resistance (NDR) of the RTD, were inserted to improve circuit stability. One end of the detector RTD is connected to the pulse generator, and Manuscript received May 7, 2012. Manuscript revised July 2, 2012. † The authors are with the Graduate School of Science and En- gineering, University of Toyama, Toyama-shi, 930-8555 Japan. a) E-mail: maezawa@ieee.org DOI: 10.1587/transele.E95.C.1830 Fig. 1 The configuration of the sampler circuit based on RTDs. Fig. 2 Model I -V curve (solid line) of the RTD together with the experimental I -V curve (dashed line). the other end is connected to the input signal via a capacitor. The sampled signal is read by a DC current of the bias line. The RTD pulse generator consists of an RTD and a re- sistor together with a high pass filter (HPF). This simple pulse generator has been demonstrated to generate ultrashort pulses of 6-ps width [9]. The width of the pulse was lim- ited by the measurement apparatus, and much shorter pulse width is expected. The sine wave driving this pulse genera- tor is biased such that the main pulse is negative. Here, we will explain the operating principle of the cir- cuit using a simple piece-wise linear I -V curve of the RTD shown in Fig. 2. An experimentally obtained I -V curve is also plotted in the figure for reference. The low voltage re- gion is linear from -V p to V p . This can be achieved by de- signing the RTD structure so that the ground quantum level Copyright c  2012 The Institute of Electronics, Information and Communication Engineers