Yi-Cheng Lin

Compact Ultrawideband Rectangular Aperture Antenna and Band-Notched Designs

A simple and compact ultrawideband (UWB) aperture antenna with extended band-notched designs is presented. The antenna consists of a rectangular aperture on a printed circuit board ground plane and a T-shaped exciting stub. The proposed planar coplanar waveguide fed antenna is easy to be integrated with radio-frequency/microwave circuitry for low manufacturing cost. The antenna is successfully designed, implemented, and measured. A compact aperture area of 13 times23mm2 is obtained with promising performances, including broadband matched impedance, stable radiation patterns, and constant group delay. The correlation between the mode-based field distributions and radiation patterns is discussed. Extended from the proposed antenna, three advanced band-notched (5-6 GHz) designs are also presented as a desirable feature for UWB applications

60-GHz Four-Element Phased-Array Transmit/Receive System-in-Package Using Phase Compensation Techniques in 65-nm Flip-Chip CMOS Process

AThe 60-GHz four-element phased-array transmit/receive (TX/RX) system-in-package antenna modules with phase-compensated techniques in 65-nm CMOS technology are presented. The design is based on the all-RF architecture with 4-bit RF switched LC phase shifters, phase compensated variable gain amplifier (VGA), 4:1 Wilkinson power combining/dividing network, variable-gain low-noise amplifier, power amplifier, 6-bit unary digital-to-analog converter, bias circuit, electrostatic discharge protection, and digital control interface (DCI). The 2 × 2 TX/RX phased arrays have been packaged with four antennas in low-temperature co-fired ceramic modules through flip-chip bonding and underfill process, and phased-array beam steering have been demonstrated. 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 mm2 in the TX integrated circuit (IC) and 4.18 mm2 in the RX IC. The beam-steering measurement results show acceptable agreement of the synthesized and measured array pattern.

Novel Broadband Circularly Polarized Cavity-Backed Aperture Antenna With Traveling Wave Excitation

A novel broadband circularly polarized aperture antenna is presented that uses traveling-wave excitation as the design concept. The antenna configuration consists of a circular radiating aperture, a backed cavity, and an equiangular tapered strip outer-fed by a microstrip transmission line. Operating with a traveling wave excitation, the proposed antenna contains inherent broadband characteristics in terms of the impedance, axial ratio, and gain performances. The presented antenna is comprehensively investigated, including the working principles, design consideration, and parametric studies. In addition, the research interests are extended to a 2 × 2 antenna array. Promising results from the experimental 2 × 2 array are achieved, including the 10-dB return loss bandwidth of 70%, the 3-dB axial ratio bandwidth of 50%, and the half-power (3-dB) gain bandwidth of 40% with a maximum gain about 11 dBi. The measured and simulated results are well complied with each other.

Simple Printed Multiband Antenna With Novel Parasitic-Element Design for Multistandard Mobile Phone Applications

A simple printed multiband antenna with parasitic-element design for multi-standard handheld terminals in mobile communications is presented. The proposed antenna performs three resonance modes covering six bands of wireless standards, including GSM, GPS, DCS, PCS, UMTS, and LTE 2300/2500. In geometry, the antenna simply consists of two metal stubs. One is an L-shaped driven stub working as a feeder and an embedded transmission line. The other is a U-shaped parasitic stub working as a radiator. With fully printed and simple configuration, the proposed antenna design is cost effective in manufacturing and easy to optimize for different frequency bands. Parametric studies and the design rule are included. The antenna occupies an area of 18 × 37 mm2 on top of a system board. This communication covers the details of the antenna design, working principle, and the performances of simulation and measurement.

MMICs in the millimeter-wave regime

On the basis of the current status of silicon based MMICs, it is possible to implement millimeter-wave SOC in silicon-based technologies that include the antenna, a medium-power amplifier, a transceiver, an LO (frequency synthesizer), and baseband circuits in a single chip. With certain interconnection schemes, such as flip-chip, to connect the chip to the substrate, it is also possible to integrate the best possible chips for a millimeter-wave communication system. Currently, CMOS is the best choice for the baseband circuits, while GaAs and InP MMICs can provide the best noise/power performance in the transceiver. High-efficiency antennas can be implemented directly on the packaging substrate. The SIP approach has the optimal combinations of the components for the best performance in a particular system. For example, a system in a package including CMOS baseband circuits, GaAs/InP-based transceiver, high-efficiency antenna, and high-power amplifier can achieve the best system characteristics. As we have discussed, the scope of SOC can be expanded along with more advanced MMIC fabrication technology and design techniques.

A Compact Sequential-Phase Feed Using Uniform Transmission Lines for Circularly Polarized Sequential-Rotation Arrays

A compact sequential-phase (SP) feed for circularly polarized sequential-rotation (SR) arrays is presented. Unlike traditional SP feed using multiple segments for impedance transformations, the presented SP feed employs only a single-stage transition where the transmission line width is uniform, making the whole SP feed very compact and neat in layout. The radial design of SP-feed lines to antenna elements may further facilitate the optimization work in adjusting the element spacing. Two miniature square SP feeds of the sizes λg/4 and 3 λg/8 are given and compared. Experimental prototypes were built and verified with measured results. The proposed compact SP feed can be extended to 2N × 2N feeding networks, and is very suitable for large-scale printed CP arrays.

A Mode-Based Design Method for Dual-Band and Self-Diplexing Antennas Using Double T-Stubs Loaded Aperture

A mode-based design method for dual-band and self-deplexing antennas is presented. By analyzing the E-field distributions and cut-off frequencies of the individual modes in a T-stub loaded aperture, we selected two proper modes for the antenna designed for dual-frequency operations. The desired feature is that at the two different frequencies, the antenna may perform the same or similar radiation characteristics including the polarization, the pattern shape, and the gain level. A rectangular aperture loaded with double T-stubs was employed for the illustration basis. The proposed method was demonstrated to the dual-band antenna and self-diplexing antenna design with promising performances. The presented dual-band antenna performed a wide range of the frequency ratio from 1.3 to 3.0 under a fixed antenna size. The proposed self-diplexing antenna achieved good port isolation better than 26 dB in both operating bands. Both illustrated antenna designs were successfully verified with built prototypes of which the simulation and measurement results were quite consistent.

Miniaturized Design of Microstrip-Fed Slot Antennas Loaded With C-Shaped Rings

A novel miniaturized design of a microstrip-fed slot antenna is presented. By properly loading a pair of C-shaped rings inside a half-wavelength slot, the fundamental resonant frequency can be significantly decreased. This letter illustrates the mechanism of miniaturization and key dimension parameter analysis. An optimized design with 50% size reduction was fabricated and measured, where very good agreement between simulation and measurement was obtained. The results show that the presented miniature slot antenna maintains the nominal radiation patterns of slot antennas with some moderate gain degradations.

A Compact Outer-Fed Leaky-Wave Antenna Using Exponentially Tapered Slots for Broadside Circularly Polarized Radiation

A novel leaky-wave slot antenna for broadside circularly polarized (CP) radiation is presented. The antenna simply consists of a slotline for the feed, an exponentially tapered slot for the radiator, and a shaped end for the terminator. Separating the feed from the curved radiating slot makes the presented antenna unique in design and compact in size. The resulting antenna yields inherent broadband characteristics of leaky-wave antennas on the input impedance, axial ratio (AR), and radiation gain. Particularly, to solve the tilt-beam problem commonly seen in leak-wave antennas, we proposed an extended dual-slot design that successfully achieved the pattern stability over a wide bandwidth. An antenna module with a reflector for unidirectional pattern applications was also developed. The measured performances of the final prototype were found to exhibit 10-dB return loss bandwidth of 40%, 3-dB AR bandwidth of 53%, and half-power gain bandwidth of 59% with CP gain level about 8 dBic. The measured and simulated results were well consistent with each other.

A Hybrid Approach for Finite-Size Fabry-Pérot Antenna Design With Fast and Accurate Estimation on Directivity and Aperture Efficiency

We present a simple hybrid approach for the design of finite-size Fabry-Pérot antennas (FPA) operated for broadside radiation. The model provides an accurate estimation on the directivity and aperture efficiency, and hence may obtain the optimal configuration of the partially reflective surface (PRS) and the antenna dimensions. The PRS properties are simulated by numerical tools. However, the overall FPA maximum directivity and the required dimensions are derived with a leaky-wave analysis and a Fourier transform method. The presented model was validated by the full-wave simulation on a classic FPA structure. Additionally, from design curves of the presented model, a PCB-based patch-patterned FPA is implemented and measured. The illustrated FPA prototype showed a realized gain of 20 dBi with an aperture efficiency of 65%. The model predictions were well consistent with the full-wave simulation and measured results.