Binh L. Pham

Triple bands antenna and high efficiency rectifier design for RF energy harvesting at 900, 1900 and 2400 MHz

We present the design and development of a novel antenna that effectively radiates at three frequency bands to harvest RF energy from cellular network frequency bands (900 MHz and 1900 MHz) and Wi-Fi sources (2.4 GHz) available in ambience. The antenna is designed using the combination of three different design techniques including composite right/left hand transmission line (CRLH). In addition, a high efficiency, sensitive triple-band rectifier is also proposed in this work. The rectifier provides a maximum conversion efficiency of 80%, 46% and 42% at 940MHz, 1.95GHz and 2.44 GHz, respectively. The experimental results demonstrate that the proposed triple-band RF energy harvesting system can collect 6.6 times more power than the single 900MHz band one and 3.4 times more power than three individual bands combined.

A High Efficiency High Power Density Harmonic-Tuned Ka Band Stacked-FET GaAs Power Amplifier

A stacked-FET power amplifier (PA) with harmonic- tuned output matching network is demonstrated using a 0.15-μm Gallium Arsenide (GaAs) technology. The fabricated PA exhibits 28.5 dBm output power, 12 dB gain and 38.4% power added efficiency (PAE). To the best of our knowledge, this is for the first time stacked-FET technique is used in combining with harmonic-tuned output network to achieve high PAE and high power density simultaneously in a GaAs PA.

A 23:1 bandwidth ratio balun on multilayer organic substrate

We present the design and development of a novel, super wide bandwidth balun on a multilayer organic Liquid Crystal Polymer (LCP) substrate. The balun has a measured bandwidth ratio of 23:1, from 80 MHz to 1860 MHz. Within the operating bandwidth, the balun achieves an input return loss of better than 10 dB, an insertion loss of better than 1 dB, an amplitude imbalance of better than 0.4 dB and a phase imbalance of better than 10 degree. The size of the balun is 40.64 mm × 40.64 mm or 0.22 λg × 0.22 λg, where λg is guided-wavelength at the center frequency of 970 MHz. This balun achieves the largest bandwidth ratio reported to date on a multi-layered printed circuit board.

A wideband composite right/left hand rectenna for UHF energy harvesting applications

We present the design of a wideband composite right/left (CRLH) rectenna for energy harvesting. The frequencies of operation are in the lower UHF frequency band from 700 MHz to 1 GHz. In the UHF band, the wavelength is long and therefore energy harvesting schemes using traditional antennas are typically large. Utilizing the CRLH antenna adds an additional degree of freedom trading size with gain. The total size of the rectenna is 164 mm × 37 mm.

A compact 29% PAE at 6 dB power back-off E-mode GaAs pHEMT MMIC Doherty power amplifier at Ka-band

In this paper, we present a compact Doherty power amplifier (DPA) in a 0.15-μm enhancement mode (E-mode) Gallium Arsenide (GaAs) pseudomorphic high electron mobility transistor (pHEMT) process at Ka-band. The 2-stage DPA uses an integrated input broadside coupler to miniaturize the die size to 2.86 mm2. The monolithic millimeter-wave integrated circuit (MMIC) DPA exhibits a measured output power of 26 dBm and a measured average gain of 12 dB. The gain bandwidth covers from 25.5 to 33 GHz. The measured peak power added efficiency (PAE) is 40% and the PAE at 6 dB output power back-off is 29%. Moreover, an adjacent channel power ratio (ACPR) of −45 dBc has been measured using a 20 MHz digitally modulated signal and digital predistortion (DPD).

Millimeter-Wave Dual-Polarized High-Isolation Antennas and Arrays on Organic Substrates

We present the design and development of dual-polarized aperture coupled stacked patch antennas with substrate embedded air cavities. The antennas, targeted for operation in the W-band (75 - 110 GHz), are realized in a multilayer organic hybrid substrate utilizing both Kapton and liquid crystal polymer (LCP). Balanced and unbalanced feedlines are investigated in order to improve isolation and mitigate coupling between orthogonal polarized ports. Measured results for the single antenna element show good performance with a beamwidth of 90 ° and a 2.6:1 VSWR bandwidth of 23 GHz, and isolation of better than 17.8 dB. An eight-element linear array is also designed, fabricated and tested. The antenna array achieves a beamwidth of 13 ° with a 2.3:1 VSWR bandwidth of 7.2 GHz. Pattern measurements were achieved utilizing a millimeter-wave diode detector circuit implemented directly on the antenna substrate.

High dynamic range X-band MMIC VGLNA for transmit/receive module

In this paper, a monolithic variable gain low noise amplifier (VGLNA) for transmit/receive module is presented. The voltage controlled attenuator (VCA) in the VGLNA helps to control the gain of the LNA for 20 dB range. This core-chip achieves a high dynamic range with the measured minimum Noise Figure (NF) of 1.2 dB and OIP3 of 29 dBm at 9 GHz. The operating bandwidth of this chip is from 7.5 GHz to 10.5 GHz. Within this band, the chip has the NF lower than 1.5 dB, the gain higher than 24 dB and the OIP3 better than 25 dBm. The 1 dB compression point is 14 dBm at the output.

A 14–31 GHz 1.25 dB NF enhancement mode GaAs pHEMT low noise amplifier

In this paper, we report a wide bandwidth low noise amplifier (LNA) fabricated in a 0.15 μm enhancement mode (Emode) gallium arsenide (GaAs) pseudomorphic high electron mobility transistor (pHEMT) process. The lna employs source degeneration along with a resistive feedback network to achieve low noise figure (NF) over a wide bandwidth. Experimental results show that the LNA exhibits a maximum gain of 30 dB and maintains higher than 25 dB from 14 to 31 GHz. The measured minimum NF is 1.25 dB along with 17.5 dBm output 1-dB compression point (OP1dB) and 28.5 dBm output 3rd order intercept point (OIP3).

High Power Monolithic pHemt GaAs Limiter for T/R Module

In this paper, a high power monolithic GaAs limiter for transmit/receive module is presented. While keeping the output power below 100 mW (20 dBm), this limiter can sustain a RF input power up to 4 Watts (36 dBm). The survival input power of this limiter can get up to 10 Watts (40 dBm). This chip obtains a wide bandwidth from 7 to 21 GHz. Within this band, the chip has the insertion loss lower than 2.3 dB and achieves only 1 dB insertion loss in the X-Band from 7 GHz to 12 GHz.