Enhanced locking range technique for divide‐by‐3 differential injection‐locked frequency divider

Abstract

A new circuit technique is proposed to enhance the locking range of divide-by-3 injection-locked frequency dividers (ILFDs) implemented using a standard 0.18 μm CMOS process. The ILFD uses a transformer feedback to increase the second harmonic and enhances the conversion efficiency of injection metal-oxide semiconductor field-effect transistor mixers. The ILFD core consumes 10.8 mW power at the supply voltage of 0.9 V and with a circuit core current of 12 mA. At the incident power of 0 dBm, the measured locking range is 4.2 GHz (37.17%), from the incident frequency 9.2-13.4 GHz.Introduction: Divide-by-3 (÷3) CMOS LC-tank injection-locked frequency dividers (ILFDs) are one of the important high-modulus ILFDs. The conventional ÷3 ILFD has limited locking range because of low conversion efficiency harmonic mixers [1][2][3][4]. The ÷3 ILFD can be designed using a single-ended [1] or dual-injection metaloxide semiconductor field-effect transistor (MOSFET) [3,4]. Recently, wider locking range ÷3 ILFDs have been designed [5-9] using a linear mixer. As locking range is one of the key parameters of an ILFD to cope with the circuit parameter drift with process, voltage and temperature, extending the locking range of the ÷3 ILFD has been an active research subject. Fig. 1 summarises the past historic direct-injection ÷3 CMOS ILFDs topologies. The first differential ÷3 ILFD [7, 10] is obtained at L 2 = 0. The second differential ÷3 ILFD [11] is obtained by using L 2 . The third differential ÷3 ILFD [9,12] is obtained by deleting L 2 . The common node of injection mixer transistors (M 3 , M 4 ) provides a second harmonic at 2ω o . The input and output frequency relation of the injection mixer in a ÷3 ILFD is given by ω RF (injection frequency) − 2ω o = ω o . In this Letter, we propose a new wideband CMOS LC-tank ÷3 ILFD shown in Fig. 2 using the transformer coupling to enhance the locking range of the ÷3 ILFD.

Frequency tuning hysteresis of a dual‐resonance divide‐by‐three cross‐coupled injection‐locked frequency divider

“…The mixer in a divide-by-three ILFD uses the following input/output frequency equation given by ω RF − 2ω o = ω o , where ω RF is the frequency of radio-frequency (RF) input and ω o is the ILFD output frequency. The second step is to increase the self-generated second harmonic signal by an injection signal in the divide-by-3 LC ILFD [14,15]. Recently, dual-injection technique has been used in the 3:1 LC ILFD [16] for locking range enhancement.…”

“…high-frequency band and low-frequency band tuning ranges for the ILFD can be found. However, (14) indicates a forbidden region is found when the parameter in the root becomes negative.…”

Wide‐locking range single‐injection divide‐by‐3 injection‐locked frequency divider

“…They are usually constructed from subwavelength size periodic metal elements. Monolayer absorber designs with minor enhancement in bandwidth have been proposed in [15]. Metamaterial-based microwave absorbers have attracted considerable attention of the researchers due to their small thickness compared with conventional absorbers, nearly unity absorption and ease of fabrication.…”

19.1 GHz 18 mW divide‐by‐3 heterodyne injection locking frequency divider in 0.18 µm CMOS technology

“…Operating at the highest operating frequency within the loop, the frequency divider entails serious challenges such as operating frequency, operating range, power consumption and so on. The injection-locked frequency divider or miller divider is able to achieve a very high frequency with low power consumption [1,2]. However, their locking ranges are quite limited, especially when working at the odd division ratio, such as divide-by-3 operation.…”

“…A better solution is to increase the locking range with inductive harmonic enhancement so that the divider can cover desired working range. Unfortunately, a large silicon area is needed in this solution [1,2]. The heterodyne phase-locking technique is proposed in [3] to obtain larger division ratio and higher operating frequency.…”