We demonstrate a broadband tunable third-order intermodulation distortion (IMD) cancellation architecture using a left-handed transmission line (LHTL)-based phase shifter for a feedforward amplifier. The fabricated circuit reduces the thirdorder IMD of the main amplifier up to 17 dB after adjusting for any frequencies between 1.5 and 2.4 GHz when the frequency difference between the two tones is 2 MHz. In addition, the circuit maintains a spurious-free dynamic range that is greater than 55 dBc at the output. This effective broadband third-order IMD cancellation method is possible because of the broadband and linearly phase-tunable characteristics of the LHTL-based phase shifter.

In this study, we perform a low‐power wireless power transfer experiment to efficiently transfer energy using a phased array antenna (PAA). At the transmitting end, we used a 4 × 4 PAA consisting of left‐handed transmission line‐based compact phase shifters and inset‐feed microstrip patch antennas. The PAA used has a −30° to 30° tilting beam range with a gain ranging from 6.42 to 7.09 dBi. At the receiving end, we used an 8.9‐dBi single Yagi‐Uda rectenna at a distance of 0.8 m from the PAA and measured the converted DC powers to be between 1.5–2.2 mW for the tilting beam range. In the experiment, we limited the effective isotropically radiated power to 3 W because of concerns regarding human body safety. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:421–424, 2015

This paper describes the calculation and measurement method of gain over temperature (G/T), which is the main characteristic of an airborne active electronically scanned array (AESA) antenna. Accordingly, we calculated the G/T of an AESA antenna based on earlier approaches. Then, we measured the G/T of two same AESA antennas in an anechoic chamber. The calculated and measured G/T of the AESA antenna were −9.2 dB/K and in the range of −10.1 to −8.2 dB/K, respectively. Based on the analysis and measurement, we proved that the proposed method was valid. The proposed method can also be used for other types of phased array antenna systems.

-In this paper, we demonstrate a Non-Foster matching method for an electrically small antenna to improve the signal-to-noise ratio (SNR) of communication link. For the experiment, we used a general FM antenna whose resonance frequency is about 52-57 MHz and a floating type Linvill negative impedance converter(NIC)-based circuit as a Non-Foster matching element. By implementing the Non-Foster circuit to cover FM band, we can achieve a wide bandwidth matching covers 40-200 MHz. Our measurement shows 3-7 dB improvement of SNR for the same bandwidth though there are several spikes which means no improvement of SNR in the band.