CPW MMIC coupler based on offset broadside air-gap couplingfabricated by standard airbridge processes

A new low-loss CPW-based MMIC coupler is developed. Offset broadside coupling using the air gap between the two lines in employed to obtain tight coupling as well as low conductor loss. Moreover, the air-gap coupling is achieved using a standard MMIC airbridge process, eliminating the need for an additional dielectric process. The fabricated Ka-band coupler showed transmission and coupling losses of 3.6±0.4 dB over a wide frequency range from 20 to 39 GHz. This is better than the previous CPW coupler loss in this frequency range     

A 10- to 21-GHz, low-cost, multifrequency, and full-duplexphased-array antenna system

This paper presents a novel phased-array antenna system with multifrequency, full-duplex operation, and wide-beam scanning. The system consists of a wideband power divider, a low-loss and low-cost multiline phase shifter controlled by dual piezoelectric transducers (PETS), a four-channel multiplexer, microwave monolithic integrated circuit (MMIC) amplifiers, and a stripline-fed Vivaldi antenna array. The multiline PET phase shifter has a low perturbation loss of less than 2 dB and a total loss of less than 4 dB up to 40 GHz, with a maximum phase shift of 650°. Using dual-aligned PETS for bidirectional phase shifting results in wide scan angles of 38.6°, 37.6°, 43°, and 40° for the four channels at 10, 12, 19, and 21 GHz, respectively. The four-channel diplexer demonstrates low insertion loss with high isolation between channels. The new multifrequency phased-array system provides wide-beam scanning and full-duplex capability using a simple, low-cost architecture. The system can be used for applications in mobile satellite communications     

振荡型有源集成天线

研制中心频率为18 GHz的振荡型有源集成天线,包括微带天线设计、单片压控振荡器(MMIC VCO)的设计及微带天线与单片压控振荡器二者的集成。微带天线的芯片面积为4.5 mm×3.5 mm,增益为3.67 dB,中心频率为18.032 GHz,最小输入驻波系数为1.098;单片压控振荡器芯片面积1.1 mm×1.0 mm,调谐范围为15.978～18.247 GHz,输出功率大于6 dBm。振荡型有源集成天线的方向图测试结果与微带天线的特性符合,该振荡型有源集成天线能够正常工作。     

A 20 GHz Steerable Array Antenna Using 3-bit Dielectric Slab Phase Shifters on a Coplanar Waveguide

A simple steerable array antenna is designed and developed using a movable dielectric phase shifter. The change of effective dielectric constant at different dielectric slab positions on a coplanar waveguide is used as the phase shifter. The impedance matching and desired phase shift conditions are satisfied at two slab heights, and the reflection is designed to be minimized at these slab positions. The low-loss dielectric material is used as the dielectric slab and is placed close to a coplanar transmission line with airgap. The 4times4 steerable array antenna with the phase shifters is designed and fabricated at 20 GHz. The H-plane radiation patterns are measured at different phase shift positions and compared with the expected results     

MMIC family for DBS down-converter with pulse-doped GaAs MESFETs

A monolithic microwave integrated circuit (MMIC) family was demonstrated as a low-noise block (LNB) downconverter for use in direct broadcast satellite (DBS) receivers operating from 11.7 to 12 GHz. A 12-GHz low-noise amplifier (LNA), a 12-GHz mixer (MIX), a 10.7-GHz dielectric resonator oscillator (DRO), and a 1-GHz IF amplifier (IFA) were designed with GaAs MMIC technology. These MMIC chips were designed to form a complete LNB downconverter function with the exception of the dielectric resonator. The most significant result of this work is that practical low-noise performance can be achieved without the use of high-electron-mobility transistors (HEMTs) in a preceding stage of the MMIC LNB downconverter. Almost noise-free satellite broadcast TV pictures were seen by using a parabolic antenna, 40 cm in diameter, without needing any additional circuit adjustment     

A 90-100 GHz double-folded slot antenna

A double-folded slot antenna (DFS) has been designed, fabricated, and tested at 90-100 GHz. The antenna shows a very wideband impedance around 20 Ω from 85 to 110 GHz. The low impedance is compatible with superconductor-insulator-superconductor (SIS) junctions, Schottky diodes or high electron mobility transistor (HEMT) amplifiers, which require a low impedance at millimeter wave frequencies. The antenna is placed on a dielectric lens to synthesize a semi-infinite substrate and realize high-directivity patterns. The measured radiation patterns agree very well with theoretical calculations and demonstrate symmetric main beams and sidelobe levels below -15 db over a 10% bandwidth. The double folded slot antenna is an attractive candidate for low-cost wideband millimeter-wave monolithic microwave integrated circuits (MMIC) front ends     

A millimeter wave dielectric waveguide antenna

This paper describes the theoretical and experimental results of a novel leaky-wave antenna incorporating a homogeneous dielectric transmission line and radiating aperture into a single structure. The primary objective of this investigation is to demonstrate the ability to control aperture radiation by simply cutting slots into a metal-free dielectric transmission line. Experimental line source antennas with identical periodic slots were designed to operate in the 35 GHz frequency region. The successful performance of these antennas resulted in the design of a dielectric line source antenna with a symmetrical amplitude taper which provided a lower sidelobe level. The design represents a significant breakthrough in achieving affordable, low-loss, lightweight antennas in the millimeter wave region. The most significant applications for this type of antenna include radar surveillance and tactical missile-seeker terminal guidance.     

A 220 GHz Single-Chip Receiver MMIC With Integrated Antenna

This letter presents the design and characterization of a 220 GHz microstrip single-chip receiver monolithic microwave integrated circuit (MMIC) with an integrated antenna in a 0.1 mum GaAs metamorphic high electron mobility transistor technology. The receiver MMIC consists of a novel slot-square substrate lens feed antenna, a three-stage low noise amplifier, and a sub-harmonically pumped resistive mixer. The receiver MMIC is mounted on a 12 mm silicon substrate lens which focuses the radiation from the calibration loads to the on-chip antenna through an opening in the backside metallization of the MMIC. The double sideband noise figure of this quasioptical receiver is as low as 8.4 dB (1750 K) at 220 GHz including the losses in the antenna and in the lens. To the best of the authors' knowledge, this work demonstrates the highest integration level versus operating frequency for a MMIC ever published, regardless of technology.     

Bow-tie antennas on a dielectric half-space: Theory and experiment

A new formulation is discussed for the rigorous calculation of the radiation pattern of a bow-tie antenna of finite length and infinitesimal thickness, placed on a lossless dielectric substrate. The analysis is based on a representation of the current density on the metal surface of the antenna as a sum of an imposed (quasistatic) term and a set of current modes with unknown amplitudes. Free-space fields that are expressed in terms of continuous spectra of symmetrized plane waves are matched to the current modes using the method of moments. The resulting set of equations are solved for the unknown current amplitudes. The calculations show that for increasing bow length the antenna impedance spirals rapidly to a value predicted by transmission line theory. The theory also shows that theE-plane pattern of a two wavelength,60degbow-tie antenna is dominated by low-loss current modes propagating at the dielectric wavenumber. As the bow tie narrows, the loss of the modes increases, and the dominant wavenumber tends to the quasistatic value. Pattern measurements made at 94 GHz are shown to agree well with theoretical predictions. Measurements for a long-wire antenna, a linear array of bow-tie elements, and a log-periodic antenna are also presented.     

On the modeling of metal strip antennas contiguous with the edge ofelectrically thick finite size dielectric substrates

A solution to the problem of radiation by a narrow metal strip antenna contiguous with the edge of a dielectric substrate is presented where the substrate has parameters such that its electrical thickness is appreciable. Such an antenna may be useful at millimeter wavelengths as an integrated phased array element forming a part of a monolithic microwave integrated circuit (MMIC). A suitable geometry for this application is illustrated and an efficient computational procedure developed. Comparisons with experimental results for the input impedance and far-field radiation patterns show excellent agreement. The influence of the dielectric substrate on the performance of an antenna designed to operate at approximately 60 GHz is discussed. Two examples, the first involving the analysis of a coplanar strip transmission line fed antenna and the second involving impedance matching and control of cross-polarized radiation using a folded strip dipole, are given to illustrate practical applications of the analytical method to design problems     

Terahertz MMICs and Antenna-in-Package Technology at 300 GHz for KIOSK Download System

Toward the realization of ultra-fast wireless communications systems, the inherent broad bandwidth of the terahertz (THz) band is attracting attention, especially for short-range instant download applications. In this paper, we present our recent progress on InP-based THz MMICs and packaging techniques based on low-temperature co-fibered ceramic (LTCC) technology. The transmitter MMICs are based on 80-nm InP-based high electron mobility transistors (HEMTs). Using the transmitter packaged in an E-plane split-block waveguide and compact lens receiver packaged in LTCC multilayered substrates, we tested wireless data transmission up to 27 Gbps with the simple amplitude key shifting (ASK) modulation scheme. We also present several THz antenna-in-packaging solutions based on substrate integrated waveguide (SIW) technology. A vertical hollow (VH) SIW was applied to a compact medium-gain SIW antenna and low-loss interconnection integrated in LTCC multi-layer substrates. The size of the LTCC antennas with 15-dBi gain is less than 0.1 cm³. For feeding the antenna, we investigated an LTCC-integrated transition and polyimide transition to LTCC VH SIWs. These transitions exhibit around 1-dB estimated loss at 300 GHz and more than 35 GHz bandwidth with 10-dB return loss. The proposed package solutions make antennas and interconnections easy to integrate in a compact LTCC package with an MMIC chip for practical applications.     

Planar millimeter-wave antennas using SiNx-membranes onGaAs

Planar aperture coupled microstrip antennas for 77 GHz are demonstrated for the first time. As far as possible standard GaAs monolithic microwave/millimeter-wave integrated circuit (MMIC) technology is used to realize the antennas. The antenna patches are suspended on a thin dielectric SiN_x membrane on GaAs substrate. Therefore a novel plasma-enhanced chemical vapor deposition (PECVD) process step for the fabrication of the membranes is developed and described. The single antenna patches are coupled to a microstrip line through an aperture in the ground metallization. The method of moments in spectral domain is applied to design the patches. The feed network of a 3×1 antenna array for homogeneous excitation is simulated and optimized with a microwave design system (MDS). From reflection measurements the operation frequency of this triple patch antenna is determined to be 77.6 GHz. The farfield antenna characteristics are measured in an anechoic chamber, showing good agreement between simulated and measured results and a co- to cross-polarization isolation better than 30 dB     

一种二叉树状分形偶极子天线的设计

提出了一种基于二叉树状分形结构的分形偶极子贴片天线。该天线的介质基片采用相对介电常数为4.4,介电损耗角正切为0.02的FR4介质板,由微带线经阻抗变换后进行馈电。该天线利用分形技术实现了33%的尺寸缩减;通过平行双线结构和开U型槽技术,优化了阻抗匹配,降低了天线的谐振频率。通过仿真分析与模型优化,天线的最终尺寸为35 mm×22 mm×1.6 mm,中心工作频率为2.87 GHz,工作频率为2.77~2.97 GHz,-10 dB阻抗相对带宽为6.9%,工作频带内最小回波损耗可达-49 dB,最大增益可达2.36 dB。该天线具有小型化、阻抗匹配良好的优点,在当代小型化通信系统中具有良好的应用前景。     

Millimeter-wave silicon MMIC interconnect and coupler usingmultilayer polyimide technology

This paper reports our latest progress in developing low-loss and low-crosstalk silicon MMIC interconnects for millimeter-wave applications. The proposed silicon/metal/polyimide (SIMPOL) structure based on multilayer polyimide technology is extremely effective in reducing noise crosstalk, and also provides very low line loss, even at the millimeter-wave regime. The measurement results of the developed SIMPOL structures demonstrate extremely low noise crosstalk (<-40 dB) in the entire frequency range (up to 50 GHz), which is limited by the dynamic range of the measurement equipment, and excellent insertion loss (<-0,25 dB/mm) up to 45 GHz. In addition, the SIMPOL concept is applied for the first time successfully in the design and fabrication of branch-line hybrids at millimeter-wave frequencies, 30 and 37 GHz     

Spatial power combining for two-dimensional structures

The two-dimensional (2-D) hybrid dielectric slab-beam open and closed waveguide systems are suitable for the design of planar quasi-optical integrated circuits and devices. An open system consisting of an active E-plane amplifier array consisting of Vivaldi-type antennas with MESFET and monolithic microwave integrated circuit (MMIC) devices was investigated. The 4×1 MESFET amplifier array generated 11 and 4.5 dB of amplifier and system gain, respectively, at 7.12 GHz, and the cascade MMTC Vivaldi-type antenna produced 24 dB of amplifier gain at 8.4 GHz. Also, experiments on a new 2-D H-plane parallel-plate closed system with a stripline slot antenna is introduced, and the wavebeam-mode theory is presented. The new system minimizes scattering and isolation losses associated with open structures. The amplifier gain of the closed system based on slot antennas is compared to the open system based on Vivaldi antennas     

A low-loss unidirectional dielectric radiator (UDR) for antenna andspace power combining circuits

A low-loss unidirectional dielectric radiator (UDR) is proposed for applications to antenna and space power combining circuits. The operating principle of this novel radiator is explained in detail. Experimental prototypes using polystyrene are fabricated and measured around 9.5 GHz. A coaxial open-ended probe is used to excite this resonant radiator. A detailed study based on experimental results demonstrates interesting characteristics of a broad-beam with gain of up to 10 dBi and low cross-polarization. This type of radiator may find millimeter-wave applications in mobile and satellite communication systems     

Compact Corporate Power DividerUsing Metamaterial NRI-TLCoupled-Line Couplers

A low-loss, planar and compact metamaterial 1:4 corporate power divider design is presented. The power divider uses a cascade of three microstrip/negative-refractive-index transmission-line coupled-line couplers allowing it to be compact in the longitudinal direction. The fabricated prototype operates at 2.10 GHz and is 11.6 cm wide-designed for feeding a four-element patch antenna array. The 3 dB transmission bandwidth ranges from 0.73 GHz to 0.46 GHz for the various ports with a total insertion loss of 1.1 dB, good phase balance and better than 20 dB isolation among the output ports.     

Characterization of liquid crystal polymer for high frequency system-in-a-package applications

Liquid crystal polymer (LCP) is a promising substrate for electronics packaging. In this paper, the high frequency characteristics of LCP were investigated using a microstrip ring resonator to verify the possibility of applying the material in RF packaging. The relative dielectric constant and the loss tangent have been measured. The radiation loss of the ring is considered to accurately determine the loss tangent. A GaAs MMIC switch circuit was fabricated using LCP as substrate to demonstrate the application of this material for system-in-a-package. From the high frequency measurements, it is shown that LCP has low dielectric constant and low loss tangent in the frequency range from 1 GHz to 35 GHz. It is also found that LCP can be used in system-in-a-package applications.     

一种新型的超宽带微带转共面带状线巴伦

设计了一种新型的微带转共面带状线（coplanarStripLine以下简称CPS）的巴伦结构。它可以应用于多种常用的介质板上,具有结构紧凑、超宽带、低损耗的特点。制作了一个两端为500微带线的背靠背电路,测试得插入损耗（S21）〉-1dB、回波损耗（S11）〈-15dB的带宽为2．7GHz～7．3GHz,S21〉-4dB、S11〈-10dB的带宽为1．4GHz～15．6GHz。     

Air-Gap Transmission Lines on Organic Substrates for Low-Loss Interconnects

The fabrication of low-loss transmission line structures with an air dielectric layer is described. The channels are characterized at low frequency (10 and 100 kHz) using capacitance and loss tangent and at high frequency (500 MHz to 10 GHz) using -parameter measurements. The incorporation of an air gap resulted in structures with effective dielectric constants between 1.5-1.8 and significantly lower loss tangents. The fabrication technique could be used to create more complicated air gap transmission line structures for use in monolithic microwave integrated circuits.