Circular active integrated antenna with push-pull oscillator

A new oscillating circular patch antenna with two bipolar transistors operating in push-pull mode is presented. By using a circular instead of a rectangular patch the stability of the operating frequency is increased and second-harmonic radiated power is decreased. High radiated power and very linear frequency tuning are observed. Radiation patterns show no degradation due to patch modifications.     

Compact oscillating slot loop antenna with conductor backing

An oscillating slot loop antenna working at 4.02 GHz is realised with a low cost GaAs MESFET. A conductor backing is used to obtain a unidirectional radiation pattern     

Integrated terahertz TEM horn antenna

A terahertz transverse electromagnetic horn antenna (THz-TEMHA) monolithically integrated on a gallium arsenide substrate has been studied by means of subpicosecond pulses generated and measured on a 50 Omega coplanar waveguide. The measured reflection coefficient is below -10 dB from 100 GHz to about 1 THz. A terahertz ranging experiment was carried out in a monostatic configuration     

Integrated active antenna with simultaneous transmit-receiveoperation

The authors present results for a novel two element active transmit-receive array using dual linear polarisation and sequential rotation. Each element includes an integrated oscillator and amplifier mounted on orthogonal edges of a square patch, such that transmit and receive paths are isolated and polarisation duplexed. The array gives in excess of 55 dB transmit-receive isolation at 3.77 GHz     

Integrated complementary HBT microwave push-pull and Darlingtonamplifiers with p-n-p active loads

The authors report the microwave results of complementary heterojunction bipolar transistor (HBT) amplifiers that integrate both n-p-n and p-n-p devices on the same chip using selective molecular beam epitaxy (MBE). An HBT wideband amplifier utilizing the Darlington configuration and implementing a p-n-p active load has a gain of 7.5 dB and a bandwidth from DC to 2.5 GHz. A complementary push-pull amplifier has a saturated output power of 7.5 dBm at 2.5 GHz     

Integrated lens with dielectric horn antenna

A dielectric lens is integrated into a dielectric loaded horn antenna to produce a high efficiency feed for reflectors. The lens is designed using simple ray theory and analysed using modal matching techniques. Aperture efficiencies of up to 78% are achieved while retaining good crosspolar performance.<>     

一体化增强型美化天线应用研究

美化天线的出现较好的解决选点难、环境美化等问题。本文探讨了在美化天线的基础上引入射频放大部分,将美化天线和大功率射频放大器结合起来,不仅较好的解决选点问题,而且较好的解决弱信号、黑洞等网络覆盖问题。     

A beam-scanning and polarization-agile antenna array using mutually coupled oscillating doublers

In this paper, a two-dimensional mutually coupled oscillator array is studied for the application of a beam-scanning and polarization-agile antenna array. In the design of antenna array, a two-dimensional oscillator array is implemented in x-y plane, the polarization agility is provided by one dimension (or y-direction) and the other dimension (or x-direction) is for beam scanning. By properly tuning the free-running frequencies of these oscillators, the array radiation direction can be scanned at the selected polarization states including linearly polarized, left-hand and right-hand circularly polarized states. The maximal phase difference of /spl plusmn/180/spl deg/ between coupled oscillating signals is acquired by utilizing their second-harmonic signals. This then gives well-defined phase differences among oscillators for beam scanning in addition to the required quadrature phase difference for circular polarization. The performances of polarization agility and beam scanning for a four-element antenna array are verified experimentally and shown to have the potential for adaptive antenna array applications.     

Integrated MIMO antenna with high isolation characteristic

A novel two-channel multiple input multiple output (MIMO) antenna for handset terminals is proposed. The antenna is basically composed of two folded monopoles and is designed to operate in WiBro (Wireless Broadband Internet; the Korean version of mobile WiMax) service band, 2.30-2.39 GHz. To decrease mutual coupling between the antennas, ground wall and connecting line are added. Good impedance matching and enhanced isolation performances are observed. Radiation patterns clearly show omnidirectional performance of the proposed antenna     

Integrated circuit array antenna for short-range communicationsystems

A novel active array antenna for short-range communication applications is presented. Each element of the array consists of a `cold' MESFET which performs both the ASK demodulator and the DPSK reflection modulator functions and which is directly mounted on a rectangular microstrip resonator. The techniques used to fabricate this active antenna provide good performance at low cost and low power consumption     

Integrated active antenna array using unidirectional dielectricradiators

In this paper, design considerations and experimental investigations of an integrated active antenna for space power combining that makes use of unidirectional dielectric radiators (UDRs) are presented and discussed. Attractive electrical performance stemming from proprieties of nonradiating dielectric waveguide structures is used to design a prototype at a frequency of 14 GHz. A UDR feed circuit is implemented by microstrip lines and aperture-coupling is studied experimentally for arrays of two, four and eight radiators. Measurements show high coupling and radiation efficiencies of the proposed excitation method. A power-combining efficiency of 89% was measured and a gain of 23.1 dBi was achieved for an antenna with eight radiators and four amplifiers. It is also shown that such a circuit configuration allows the combination of planar Ku-band monolithic hybrid microwave integrated circuit and UDR components in flexible design of active array antennas     

Integrated travelling-wave antenna for nonradiative dielectric waveguide

A travelling-wave antenna for integrated use in nonradiative dielectric waveguide is described. The antenna is constructed by cutting a longitudinal slot in the waveguide side wall. Results are presented showing the comparison between measured and calculated data.     

0.18-/spl mu/m CMOS push-pull power amplifier with antenna in IC package

A novel architecture of power amplifier with antenna implemented in a ceramic ball grid array (CBGA) package is presented. The monolithic power amplifier designed in a standard 0.18- /spl mu/m CMOS technology offers 19.5 dBm maximum output power at 5.2 GHz to the antenna with the PAE of 32%. The antenna integrated in the CBGA package achieves impedance bandwidth of 3.86% and gain of 2 dBi at 5.2 GHz. Results demonstrate the feasibility of using this innovative configuration to the design of single-chip 5 GHz transmitter front-end.     

Integrated circuit ceramic ball grid array package antenna

The recent advances in such highly integrated RF transceivers as radio system-on-chip and radio system-in-package have called for the parallel development of compact and efficient antennas. This paper addresses the development of a new type of dielectric chip antenna known as integrated circuit package antenna (ICPA) for highly integrated RF transceivers. A compact ICPA of this type has, for the first time, been designed and fabricated in a ceramic ball grid array (CBGA) package format. The novel ICPA, except economical advantage of mass production and automatic assembly, has potential benefit to the system-level board miniaturization and the system-level manufacturing facilitation. The simulated and measured antenna performance of the ICPA is presented. The effects of the different physical parts of the ICPA on the antenna performance are investigated. Results show that the ICPA achieved impedance bandwidth of 4.1% and radiation efficiency of 72%, and gain of 4.8 dBi at 5.715 GHz.     

Integrated uniplanar transition for linearly tapered slot antenna

This paper presents the design, fabrication, and numerical modeling of two new uniplanar microstrip-to-coplanar strip (CPS) line transitions and a new variant of the linearly tapered slot antenna (LTSA). This new variant with an integrated uniplanar microstrip-to-coplanar strip line feed is called a V-LTSA. The advantages of these transitions in packaging and monolithic microwave integrated circuits (MMIC) integration are listed. The two transitions and the feed are modeled using finite difference time domain (FDTD) method. The overall agreement between the measured and modeled return-loss and insertion-loss characteristics of two back-to-back transitions is good. The resonance frequencies predicted by the FDTD method are within a few percentage points of the measurements. Furthermore, the V-LTSA with the feed is experimentally shown to have a wide return loss (⩽-10 dB) bandwidth, good radiation patterns, and low cross-polarization. The gain of the V-LTSA is 9 dB at the design frequency of 10 GHz. A proof-of-concept package to house the feed is experimentally evaluated and shown to have negligible effect on the antenna characteristics. This type of antenna readily integrates with MMIC packages in an array having a brick architecture. The V-LTSA has potential applications in phased arrays     

Smart antenna arrays with oscillating beam patterns: characterization of transmit diversity in semi-elliptic coverage

By applying carefully selected time-varying delays to the array elements of a smart antenna located at the base station (BS), small oscillations are generated in the beam pattern. These oscillations create a time-varying channel demonstrating intra-symbol time variation and characterized by coherence time T/sub C/. At a single-antenna mobile station (MS), the time-varying channel (with coherence time T/sub C/) creates a time diversity which is exploited to enhance the mobile's performance (by introducing oversampling to the mobile receiver). We present a channel model which characterizes the time-varying channel that results from beam pattern oscillation. We then use our channel model to evaluate the coherence time, T/sub C/, at the mobile station (MS). The channel model presented corresponds to the so-called geometric-based stochastic channel model (GSCM), with a semi-elliptic coverage area. This geometric approach allows us to stochastically model the parameters of the time-varying channel impulse response. Simulations based on the GSCM show that 7-fold time diversity can be exploited at the MS (when beam pattern movement is small), which significantly improves the MS receiver probability-of-error performance.     

Integrated four-beam dual-band antenna array fed by broadband Butler matrix

A four-beam dual-band antenna array fed by a single 4times4 Butler matrix is presented, for the first time. A broadband Butler matrix designed in a stripline technique has been used as a basic element of a feeding network. To separate signals frequency diplexers have been designed. All designed elements of the feeding network have been integrated together with two antenna rows operating in two separate frequency bands     

Integrated antenna with direct conversion circuitry for broad-band millimeter-wave communications

A compact integrated antenna with direct quadrature conversion circuitry for broad-band millimeter-wave communications is proposed. The conversion circuits include two even-harmonic mixers based on antiparallel diode pairs (APDPs). The equivalent circuit of the APDP derived here provides good agreement with the measured data from 17 to 23 GHz. Overall phase and amplitude imbalance between the in-phase/quadrature (I/Q) output channels are less than 1.2/spl deg/ and 1 dB at IFs of 10 and 100 MHz, respectively. An overall RF power conversion loss of 14.6 dB at the quadrature I/Q channels including the antenna is achieved in the frequency range from 39.75 to 40.25 GHz with a local oscillator (LO) power level of 11.8 dBm. LO leakages at 20 and 40 GHz are -31.5 and -44.8 dBm, respectively. In order to demonstrate the system capabilities for broad-band digital communication, a communication link is built with a pair of the proposed front-ends. Data transmission up to 1 Gb/s data rate for quadrature phase-shift keying modulation is demonstrated.     

Integrated-antenna push-pull power amplifiers

In this paper, the integrated-antenna concept is applied to push-pull power amplifiers (PAs). In this approach, the antenna serves as an out-of-phase power combiner and tuned load for higher harmonics. This new architecture effectively has a near-zero loss output hybrid, and results in a high-efficiency PA. The first example is a narrow-band push-pull amplifier integrated with a dual-feed patch antenna. At an operating frequency of 2.5 GHz, a maximum measured power-added efficiency (PAE) of 55% is achieved. The second example is a broadband push-pull amplifier integrated with a dual-feed slot antenna amplifier operating at 2.46 GHz which has a peak PAE of 63%, and PAE better than 55% in an 8% bandwidth. Additionally, 48% PAE is achieved with code-division multiple-access modulation and adjacent-channel power ratio better than -42 dBe at a 1.25-MHz offset     

小型化八边形基片集成波导背腔缝隙天线

提出一款新颖的W波段八边形基片集成波导(SIW)背腔缝隙天线。相较传统的缝隙天线，具有体积小、易加工、Q值高、成本低等优点，且易于成阵。通过调节天线背腔缝隙的长度、宽度，以及SIW腔体的尺寸优化天线的辐射特性，通过电磁仿真软件HFSS对模型进行仿真优化，确定了天线的最优结构。仿真实验结果表明，所设计的天线相对带宽约4.5%，方向性优良，中心频率点谐振深度<-31 dB，天线最大增益达到5 dBi，满足设计要求，验证了设计的正确性。所设计的SIW背腔缝隙天线拓宽了数字通信的可用频谱，是一种新的尝试，可为以后的研究提供新的参考思路。