Electromagnetic Wave Group - Advanced Microwave and RF-SOP Technology

 As some of the pioneers in millimeter-wave CMOS RFICs, we have demonstrated many significant results. Starting from a 63-GHz push-push VCO using 0.25-μm CMOS in 2004 [1], followed by a dc-to-70-GHz amplifier [2], 114-GHz and 131-GHz push-push VCOs [3]–[4], a 90-GHz fundamental frequency VCO with a novel ring-couple quad MOSFET [5] have been demonstrated. Broadband BPSK and IQ modulators [6], several high gain amplifiers covering 35 GHz to 108 GHz [7]–[10], broadband mixers [11]–[13] were also demonstrated. Additionally, wideband switches were developed in CMOS technologies [16], [17].

The successful development of these components enables the high level integration of millimeter-wave multifunction MMICs, such as a 46-GHz direct wide modulation bandwidth amplitude shift keying (ASK) modulator with an embedded VCO and a 60-GHz six-port CMOS transceiver [14], [15].

For 60-GHz application, several 60 GHz CMOS low noise amplifier [18]-[20] and mixer [21],[22] were demonstrated. Additionally, a 60-GHz four-element phased-array transmitter (TX) and receiver (RX) system-in-package (SiP) antenna modules with phase compensate techniques in 65nm CMOS technology are presented [23]. The 60-GHz four-element phased-array TX and RX SiP modules can achieve wide bandwidth 2-D beam steering and low power consumption. Based on phase compensation techniques, the change of radiated beam versus frequency can be corrected in free space. Acceptable agreement between synthesized and measured beam steering pattern is demonstrated with a packaged IC.

 A novel system in package (SiP) RF frontend module for X-band frequency-modulated continuous wave (FMCW) sensor has been developed [1] for short distance moving object detection. A multi-function RFIC chip realized by typical 1P6M 0.18 μm deep n-well CMOS technology, a multi-layer 180° hybrid [2] and two embedded ring filters [3], two sets of antenna arrays, and all other necessary components are all integrated into a miniaturized module no larger than 35 mm×35 mm LTCC substrates. In addition to the 3.5 dBm transmitter output and 6 dB receiver conversion gain of the RFIC block, a 7.5 dB-gain single-arm fractional spiral antenna element is backed with an electromagnetic bandgap (EBG) structure [4] for maximizing the detection range within the volume limit of the module. Each building block has been tested individually for verifying the functionality of the whole module. Besides the basic functionality of distance detection, such design can accomplish angle detection as well by comparing the sum and difference patterns of an antenna element pair at receiving end.

Another SiP application recently demonstrated is a 60 GHz phase array antenna module. The transceiver (TX/RX) design is based on the all-RF architecture in 65-nm CMOS technology with 4-bit RF switched LC phase shifters, phase compensated VGA, 4:1 Wilkinson divider/combiner, variable-gain LNA, PA, 6-bit unary D/A converter, bias circuit, ESD protection, and DCI. It has been packaged with four antennas in LTCC modules through flip-chip bonding and underfill process. A careful transition design is proposed, which consists of two microstrip-to-via transitions and a multilayered through-hole via with four ground vias, exhibiting low return loss and low insertion loss over a wide frequency range of d.c. up to 67 GHz [5]. The entire beam-steering functions are digitally controllable, and individual registers are integrated at each front-end to enable beam steering through the DCI. The four-element TX array results in an output of 5 dBm per channel. The four-element RX array results in an average gain of 25 dB per channel. The four-element array consumes 400 mW in TX and 180 mW in RX and occupies an area of 3.74 mm in the TX integrated circuit (IC) and 4.18 mm in the RX IC [6].