Jeng-Hau Lu

Highly-miniaturized 2-channel mm-wave radar sensor with on-chip folded dipole antennas

This paper describes a miniaturized 2-channel system-on-chip radar sensor in a SiGe BiCMOS technology. It includes on-chip folded dipole antennas that utilize a localized backside etching technique with a novel selective etching approach that is able to improve the radiation efficiency and the mechanical stability of the chip. The transceiver is equipped with a 30-GHz VCO that is complemented with a frequency quadrupler to generate a 120-GHz carrier signal. The 2 transmit channels can be combined to increase the effective isotropic radiated power by 6 dB and to implement a SIMO radar. The transceiver also includes BPSK modulators as well as I/Q receivers and can be utilized to build a flexible MIMO radar using frequency-modulated continuous-wave with time and delta-sigma modulator-based frequency division multiplexing as well as pseudo-random noise radar techniques. Radar measurement using digital-beamforming method with 10-GHz modulation bandwidth was performed to show the applicabilty of the proposed system.

Side Lobe Suppression of a Short Leaky-Wave Antenna by Phase Constant Tapering: Analysis and Design

Uniform leaky-wave antennas (LWAs) with limited length have suffered from the presence of high-level side lobes, which could lead to the reception of unwanted noise especially when the LWA is short. This communication examines how the phase constant of a short LWA can be manipulated to achieve side lobe suppression. The tapering of the phase constant is shown to result in higher order “image patterns,” which can be used advantageously for side lobe suppression. Validation of this principle is given by a cosine-shaped width-tapering profile design of a half-mode substrate-integrated waveguide (HMSIW) LWA. The measured results show that the side lobe level (SLL) of a short (1.4 λ0) HMSIW LWA has been suppressed to below -16 dB in the entire space wave leakage region using this tapering profile.

A three-order equal-ripple band-pass filtering antenna design using capacitive-gap coupled asymmetrical-CPW resonator

In this paper, a three-order equal-ripple bandpass filtering antenna design using capacitive-gap coupled asymmetrical-CPW resonator is presented. The asymmetrical coplanar waveguide consists of the left-side finite ground plane, which is similar to a strip and the right-side ground plane, which is a big ground plane. The operating bandwidth (5150-5825 MHz) was designed using conformal mapping technique and microwave-filter theory. However, it can be an antenna candidate due to the asymmetrical-CPW effect verified by simulated results, which show a -10 dB insertion loss and 70 % radiation efficiency.

A tapered single-conductor strip leaky-wave antenna with suppressed back lobe

A tapered single-conductor leaky-wave antenna is presented. By tapering the width of the single conductor strip, the front to back ratio is about 15 dB from 4.5 GHz to 6 GHz. A wide-band balun is used to support the proposed antenna operate from 4.5 GHz to 6.55 GHz with the return loss > 10dB.