Design of IF-RF-Based Heterodyne Transmitter Using Current Steering DAC with 5.4 GHz Spur-Free Bandwidth

Abstract

The paper presents an intermediate frequency (IF) radio frequency (RF)-based heterodyne transmitter using current steering DAC. In the proposed design, a single digital AND gate is used as IF mixer and modulator of input data. This IF signal is further mixed with local oscillator signal in the current steering DAC to obtain RF output signal. The AND gate-based IF modulator converts input signal to square wave. This square wave does not contain even harmonics and consists of odd harmonics, which reduces harmonic mixing products. In addition, double differential architecture has been used in current steering DAC to cancel even harmonics. With cancellation of even harmonics in IF and RF signals, the output spectrum consists of only odd multiple of RF output frequency, resulting in spur-free bandwidth of 5.4 GHz for the RF output frequency of 2.4 GHz. The proposed transmitter employs 64-quadrature amplitude modulation which gives an output power of 446 m dBm without a power amplifier. Monte-Carlo simulations have been performed to verify the reliability of the circuit against process and mismatch variations, and it has been found that the circuit parameters are less sensitive to process variations.

KEYWORDS:

• Intermediate frequency (IF)
• Radio frequency (RF)
• RF-DAC
• Super heterodyne transmitter
• Spur-free

ACKNOWLEDGEMENTS

This work has been performed using the resources of VLSI Laboratory developed under Special Manpower Development Program – Chip to System Design (SMDP-C2SD) project funded by Ministry of Electronics and Information Technology (MeitY), Government of India.

DISCLOSURE STATEMENT

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Abhishek Kumar

Abhishek Kumar obtained the BTech degree in electronics and instrumentation engineering from Galgotias College of Engineering and Technology, Greater-Noida, Uttar Pradesh and MTech degree in VLSI and embedded system from KIIT University, Bhubaneswar. He worked at MNNIT Allahabad as RA in SMDP-C2SD project and worked in designing and fabrication of transmitter module in the project. His areas of interest are DAC and transmitter design.

Santosh Kumar Gupta

Santosh Kumar Gupta received his BE degree in electronics & communication engineering from Govind Ballabh Pant Engineering College, Pauri, Uttarakhand in 2000, MTech in communication engineering from Indian Institute of Technology Bombay, Mumbai, India in 2002, and PhD from National Institute of Technology Silchar, Assam, India in 2014. Presently, he is working as an associate professor in ECED at MNNIT Allahabad, Prayagraj, India. His research interests include VLSI design, simulation and modeling of semiconductor devices. He is an author/co-author of several research papers in international/national journals and conferences. Email: [email protected]

Vijaya Bhadauria

Vijaya Bhadauria obtained BE degree in electrical engineering and ME in control and instrumentation in 1984 and 1986, respectively, from MNREC, Allahabad, UP. She joined as a faculty member in ECE Department of MNREC, UP in 1986. She obtained her PhD degree in electronics engineering in 2012 from ECE Department of MNNIT Allahabad (previously known as MNREC, Allahabad), and currently serving as a professor. Her area of interest is analog IC design and VLSI design. Her field of interest includes Digital and Analog VLSI IC design. She is an author/co-author several research papers in international journals and conference. Email: [email protected]