Sang Young Kim

A 76–84-GHz 16-Element Phased-Array Receiver With a Chip-Level Built-In Self-Test System

This paper presents a 16-element phased-array receiver for 76-84-GHz applications with built-in self-test (BIST) capabilities. The chip contains an in-phase/quadrature (I/Q) mixer suitable for automotive frequency-modulation continuous-wave radar applications, which is also used as part of the BIST system. The chip achieves 4-bit RF amplitude and phase control, an RF to IF gain of 30-35 dB at 77-84 GHz, I/Q balance of and at 76-84 GHz, and a system noise figure of 18 dB. The on-chip BIST covers the 76-84-GHz range and determines, without any calibration, the amplitude and phase of each channel, a normalized frequency response, and can measure the gain control using RF gain control. System-level considerations are discussed together with extensive results showing the effectiveness of the on-chip BIST as compared with standard S-parameter measurements.

A Low-Power BiCMOS 4-Element Phased Array Receiver for 76–84 GHz Radars and Communication Systems

This paper presents a 76-84 GHz low-power 4- element phased array receiver built using a 0.13 μm BiCMOS process. The power consumption is reduced by using a single-ended design and alternating the amplifiers and phase shifter cells to result in a low noise figure at a low power consumption. A variable gain amplifier and an 11° trim bit are used to correct for the rms gain and phase errors at different operating frequencies. The phased array consumes 32 mW per channel and results in a gain of 10-19 dB at 76-84 GHz, a noise figure of 10.5 ±0.5 dB at 80 GHz and an rms gain and phase error <;0.8 dB and <;7.2 °, respectively, up to 81 GHz, and <;1.1 dB and 10.4° up to 84 GHz. The phased array also shows a channel to channel coupling of <; - 30 dB up to 84 GHz. To our knowledge, this work presents state-of-the-art on-chip performance at W-band frequencies.

A 76–84 GHz 16-element phased array receiver with a chip-level built-in-self-test system

A 16-element phased array receiver with built-in-self test (BIST) is demonstrated at 76-84 GHz. The BIST technique employs a miniature capacitive coupler located at the input port of each phased-array channel, and uses the receiver I/Q down-converter to measure the amplitude and phase of each channel. This allows for measuring the response of individual channels if one channel is turned on at a time, and an on-chip array factor if several channels are turned on and the phase between them is varied. BIST measurements done at 76-84 GHz agree very well with S-parameter measurements with a matched load and an open circuit load at each port, and show that this technique can be used to greatly lower the testing cost and improve the self-calibration of mm-wave phased-array RFICs.

An Improved Wideband All-Pass I/Q Network for Millimeter-Wave Phase Shifters

This paper presents the design and analysis of an improved wideband in-phase/quadrature (I/Q) network and its implementation in a wideband phased-array front-end. It is found that the addition of two resistors (Rs) in the all-pass I/Q network results in improved amplitude and phase performance versus capacitance loading and frequency, which is essential for wideband millimeter-wave applications. A prototype 60-80-GHz phased-array front-end based on 0.13-μm SiGe BiCMOS is demonstrated using the improved quadrature all-pass filter and with 4-bit phase-shifting performance at 55-80 GHz. Application areas are in wideband millimeter-wave systems.

A Low-Loss Compact Linear Varactor Based Phase-Shifter

Design trade-offs are presented for varactor-based variable phase-shifters in terms of size, tuning range, bandwidth/phase linearity and large-signal performance. Based on this study, a compact, low-loss (0.6dB/90deg @ 1.0 GHz), wideband and extremely linear varactor-based phase shifter is presented.

Highly dense microwave and millimeter-wave phased array T/R modules using CMOS and SiGe RFICs

We have used silicon technologies to build highly dense phased array for X to W-band applications. Typical designs include an 8-element 8–16 GHz SiGe phased array receiver, a 16-element 30–50 GHz SiGe transmit phased array, a miniature (&#60; 3mm2) and low power (&#60;100 mW) CMOS phased array receiver at 24 GHz, and a 4-element SiGe/CMOS Tx/Rx phased array at 34–38 GHz with 5-bit amplitude and phase control, a 2-antenna 4-simultaneous beam phased array chip at 15 GHz. Also, a miniature 8×8 Butler Matrix with &#60; 3 dB loss in 0.13 um CMOS has been developed for multibeam applications. It is shown that silicon chips can be used to lower the cost of phased arrays with a significant impact at Ku, K and W-band applications where there is so little available space behind each antenna element due to the very small element area.

Highly dense microwave and millimeter-wave phased array T/R modules and Butler matrices using CMOS and SiGe RFICs

We have used silicon technologies to build highly dense phased array for X to W-band applications. Typical designs include an 8-element 8–16 GHz SiGe phased array receiver, a 16-element 30–50 GHz SiGe transmit phased array, a miniature (< 3mm2) and low power (<100 mW) CMOS phased array receiver at 24 GHz, and a 4-element SiGe/CMOS Tx/Rx phased array at 34–38 GHz with 5-bit amplitude and phase control, a 2-antenna 4-simultaneous beam phased array chip at 15 GHz. Also, a miniature 8×8 Butler Matrix with < 3 dB loss in 0.13 um CMOS has been developed for multibeam applications. It is shown that silicon chips can be used to lower the cost of phased arrays with a significant impact at Ku, K and W-band applications where there is so little available space behind each antenna element due to the very small element area.

Built-in self test systems for silicon-based phased arrays

Phased array silicon chips with built-in-self-test (BIST) have been demonstrated at X-band and W-band using integrated couplers and on-chip receiver circuitry. In the X-band chip (2-element phased array), a dedicated I/Q receiver is built into the chip, while in the W-band case (self-contained 16-element array), the standard I/Q receiver is used for BIST functionality. The BIST is accomplished using a very low loss coupler at the input of each channel which does not introduce additional loss and noise. Measurements on the X-band and W-band chips indicate that BIST results in accurate phase and gain measurements for every phased-array channel on the chip, and allows the measurement of an on-chip array factor, all at microsecond speeds. The BIST can also measure the frequency response of every channel. It is expected that BIST functionality will greatly reduce the cost of phased array testing and allow for on-site calibration and control.

A low-distortion, low-loss varactor phase-shifter based on a silicon-on-glass technology

A varactor-tuned continuously variable phase shifter based on an all-pass network is presented. Design equations for this phase shifter network are derived and presented. The phase shifter achieves an IIP3 of 52 dBm with 10 MHz tone-spacing at 2 GHz and loss of 2.3-3.7 dB with continuous 180deg phase shift at 2 GHz. The total chip size including pads is 2900 mum X 2200 mum.

An 18-20 GHz Subharmonic Satellite Down-Converter in 0.18μm SiGe Technology

This paper presents the design and implementation of a 18-20 GHz satellite down-converter receiver with a 10.5 GHz local oscillator. The circuit design is single-ended for minimal area and current consumption, and for compatibility with a GaAs low-noise pre-amplifier and a coaxial output transmission-line. The RF, LO and IF ports are ESD protected using on-chip diodes. The down- converter results in a measured gain of 35-40 dB, an output P1dB of +2.4 dBm, and a noise figure of 4.8-9.8 dB for an input frequency of 18-20 GHz (IF of 3-1 GHz). The required LO power is 2-3 dBm. The measured IIP3 is -36 dBm at 19 GHz. The chip consumes 31.5 mA from a 2.5 V supply, and 55% of the current is used for the output 50 W driver (17.3 mA). The chip is very small with a size of 1.1×0.7 mm including all pads and is built using a commercial 0.18-μm SiGe technology.