Design and analysis of a WLAN CMOS power amplifier using multiple‐gated transistor technique

This article focused on 5.2 GHz highly integrated power amplifier for IEEE 802.11a WLAN application. Multiple‐gated transistor technique was used to improve linearity. A new approach for choosing the bias voltage of auxiliary transistor by analyzing the shift of gate bias is used in the design. The simulated results of the proposed two‐stage differential power amplifier indicate 25.28 dBm P_1‐dB, 32.87% PAE, and 26.18 dBm saturated output power with a 5.2 dB P_1‐dB improvement compared to conventional single transistor amplifier. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

A 4‐bit ultra‐wideband complementary metal‐oxide‐semiconductor attenuator with low root‐mean‐square amplitude error

This article presents the 4‐bit ultra‐wideband complementary metal‐oxide‐semiconductor (CMOS) attenuator in a standard 0.18‐μm CMOS process. This design adopts switched bridge‐T type topologies for each attenuation bit. Based on insertion losses and input P_1‐dB considerations, the circuit performances can be optimized by the proper bit ordering arrangement. Therefore, the bit ordering 0.5‐4‐2‐1 dB is employed in the 4‐bit attenuator. Moreover, series inductors are added between each bit to further improve the input and output return losses. Measured results demonstrate that the attenuation range of the circuit is 7.5 dB with 0.5 dB step and the root‐mean‐square (RMS) amplitude error is between 0.11 and 0.13 dB from 3.1 to 10.8 GHz. The differences between simulated and measured RMS amplitude errors are less than 0.2 dB, which demonstrates the good agreement and feasibility of the design concept. The measured input P_1‐dB is 15 dBm at 5 GHz and the chip area is 1.12 mm² including all testing pads.     

A systematic design of 1.5–9 GHz high power–high efficiency two‐stage GaAs PHEMT power amplifier

In this article, a systematic design approach for a Class‐A operated wideband power amplifier is presented. The power amplifier structure comprises of two transistors in the cascaded single stage traveling wave amplifier topology. A power amplifier was designed by using the systematic approach and fabricated with 0.25 μm GaAs PHEMT MMIC process. The amplifier has an area of 3.4 × 1.4 mm². Measurement results show that almost flat gain performance is obtained around 15 dB over 1.5–9 GHz operating bandwidth. In most of the band, with the help of a wideband load‐pull matching technique, the amplifier delivers P_o,sat and P_o,1dB of around 30 dBm and 28 dBm where the corresponding power added efficiencies are >50% and >36%, respectively. It is shown that the proposed design approach has the advantage of simple and systematic design flow and it helps to realize step‐by‐step design for the designers. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:615–622, 2014.     

CMOS stacked folded differential structure power amplifier for high power RF application

This article describes the feasibility of a Power Amplifier (PA) in 0.13 μm CMOS technology from STMicroelectronics for high power applications. To obtain a high output power with a good linearity, a new topology called Stacked Folded Differential Structure (SFDS) is proposed. It allows obtaining similar power performances to a PA with DAT in a lower die area. This PA provides 23 dBm of maximum output power (P_max) with 20% of power added efficiency (PAE) at 1.95 GHz. The linear gain is equal to 11 dB and the output power at 1 dB compression point (OCP₁) achieves 21 dBm. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.     

18‐31 GHz GaN wideband low noise amplifier (LNA) using a 0.1 μm T‐gate high electron mobility transistor (HEMT) process

GaN technology has attracted main attention towards its application to high‐power amplifier. Most recently, noise performance of GaN device has also won acceptance. Compared with GaAs low noise amplifier (LNA), GaN LNA has a unique superiority on power handling. In this work, we report a wideband Silicon‐substrate GaN MMIC LNA operating in 18‐31 GHz frequency range using a commercial 0.1 μm T‐Gate high electron mobility transistor process (OMMIC D01GH). The GaN MMIC LNA has an average noise figure of 1.43 dB over the band and a minimum value of 1.27 dB at 23.2 GHz, which can compete with GaAs and InP MMIC LNA. The small‐signal gain is between 22 and 25 dB across the band, the input and output return losses of the MMIC are less than ?10 dB. The P_1dB and OIP3 are at 17 dBm and 28 dBm level. The four‐stage MMIC is 2.3 × 1.0 mm² in area and consumes 280 mW DC power. Compared with GaAs and InP LNA, the GaN MMIC LNA in this work exhibits a comparative noise figure with higher linearity and power handling ability.     

A highly efficient concurrent dual‐band GaN class‐AB power amplifier at 1.84 GHz and 3.5 GHz

This article presents the design, simulation, implementation, and experimental results of a highly efficient, concurrent dual‐band, gallium nitride (GaN), class‐AB power amplifier (PA) at two frequencies: 1.84 and 3.5 GHz. It proposes a novel dual‐band bandpass filter (DBBPF) with quad‐section stepped‐impedance resonators (SIRs) capable of rejecting the annoying frequencies of the second and third harmonics in the dual‐band. The proposed DBBPF was applied in the design of a dual‐band PA using a packaged 10 W GaN transistor. The PA prototype maintained a peak power‐added efficiency (PAE) of 75.3% at the 1.84 GHz frequency and 64.5% at the 3.5 GHz frequency. For a continuous wave output power of 40.9 dBm, the measured gain was 13 dB in the two frequency bands. Linearized modulated measurements, concurrently using 10 MHz quadrature amplitude modulation (16 QAM) signals and worldwide interoperability for microwave access (WiMAX) signals, showed an average PAE of 48.5% and 39.8% and an adjacent channel leakage ratio of ?46 and ?45 dBc with an average output power of 37.8 and 36.8 dBm at the two frequency bands, respectively. This PA is used for wireless systems. It is especially useful in standard simultaneous global system for mobile (GSM) and WiMAX wireless systems.     

Gain enhancement and mutual coupling reduction of multiple‐intput multiple‐output antenna for millimeter‐wave applications using two types of novel metamaterial structures

A method to significantly increase the gain and reduce the mutual coupling of microstrip multiple‐intput multiple‐output (MIMO) antenna based on metamaterial concept is presented. The μ‐negative and ε‐negative features of the proposed modified peace‐logo planar metamaterial (MPLPM) and two‐sided MPLPM (TSMPLPM) structures are calculated. The antenna structure consists of eight MPLPM slabs and two TSMPLPM, which are embedded in azimuth plane of a MIMO antenna vertically. The dimensions of MIMO antenna are 28 × 16 × 6.3 mm³ at 40 GHz. As a result, a compact MIMO antenna is simulated in comparison with primary microstrip structures. The corresponding return‐loss of the antenna is better than 10 dB over 34.5 to 45.5 GHz for Ka‐band applications. Good consent between the measured and simulated result is tacked. The maximum simulated gain of the structure is 15.5 dB at 40 GHz, creating a maximum gain improvement of 11.5 dB in comparison with a MIMO antenna without any metamaterial combinations. The value of the insertion‐loss (isolation) is 33 dB, which has improved by more than 25 dB compared to the conventional sample.     

CSRR‐loaded T‐shaped MIMO antenna for 5G cellular networks and vehicular communications

This article proposes a multiple input multiple output (MIMO) antenna for 5G‐based vehicular communication applications. The designed MIMO antenna consist of two element iterated T‐shape antenna with defected ground structure (DGS) and split ring resonator. The antenna providing reflection coefficient S₁₁ s₁₁ ≤10 dB and bandwidth of 6.3 and 3.96 GHz over the frequency range of 26.83 to 33.13 GHz and 34.17 to 38.13 GHz, respectively. For the suitable future vehicular millimetric wave communications, this antenna achieved resonant frequencies at 28, 33, and 37 GHz. The designed antenna has achieved peak gain of 7.11 dB in operating band. It is fabricated on 12 x 25.4 x 0.8 mm³ Rogers RT duroid 5880 substrate with dielectric constant (ε_r) of 2.2. The antenna is placed on vehicle in virtual environmental using ANSYS SAVANT tool and the simulated results are showing good matching with the measured results of proposed MIMO antenna.     

Epsilon‐shaped circularly polarized strip and slot‐loaded ultra‐wideband antenna for Ku‐band and K‐band

A compact epsilon‐shaped (ε) ultra‐wideband (UWB) antenna for dual‐wideband circularly polarized (CP) applications has been investigated in this article. It consists of a stepped stub loaded modified annular ring‐shaped radiator and modified CPW ground plane. The ground plane is loaded with two semicircular notches and a spiral‐shaped slot. The impedance bandwidth (IBW) is 97.02% (10.4‐30 GHz) along with an overall footprint of 20 × 20 mm². The fractional axial ratio bandwidth (3‐dB ARBW) for two wide bands is 38.50% (13.30‐19.64 GHz) and 6.45% (26.25‐28.00 GHz), respectively. The proposed antenna is left‐hand circularly polarized with a peak gain of about 5.09 and 5.14 dB in both 3‐dB ARBW bands. The proposed antenna is dominating other reported CP antenna structures in terms of number of CP bands, 3‐dB ARBW, IBW, peak gain, and dimensions.     

Wideband bandpass filtering branch‐line balun with high‐isolation

The wideband bandpass filtering branch‐line balun with high isolation is presented in this paper. The proposed balun can be designed for wideband performances by choosing a proper characteristics impedance of input vertical transmission line and odd‐mode impedance of parallel‐coupled lines. The proposed balun was designed at a center frequency (f₀) of 3.5 GHz for validation. The measured results are in good agreement with the simulations. The measured power divisions are ?3.31 dB and ?3.24 dB at f₀ and ?3 ± 0.17 dB within the bandwidth of 0.95 GHz (3 GHz to 3.95 GHz). The input return loss of 24.09 is measured at f₀ and higher than 20 dB over the same bandwidth. Moreover, the measured output losses are better than 11 dB within a wide bandwidth. The isolation between output ports is 20.32 dB at f₀ and higher than 13.2 dB for a broad bandwidth from 1 GHz to 10 GHz. The phase difference and magnitude imbalance between two output ports are 180° ± 4.5° and ± 0.95 dB, respectively, for the bandwidth of 0.95 GHz.     

A novel millimeter‐wave dual‐band circularly polarized dielectric resonator antenna

In this article, a novel dual‐band circularly polarized (CP) dielectric resonator antenna (DRA) for millimeter‐wave (MMW) band is presented. The rectangular dielectric resonator with layered truncated corners is excited by a microstrip‐coupled cross‐slot. CP radiations in the lower band are realized by utilizing two quasi‐TE₁₁₁ modes operating at 21.7 GHz and 23.8 GHz, while CP radiations in the upper band are obtained by exciting a quasi‐TE₁₁₃ mode at 28.2 GHz. The dual‐band DRA is fabricated and measured. Due to the higher order mode, the average gain of the DRA in the upper band is about 3 dB higher than that in the lower band. The measured impedance bandwidths (|S₁₁| < ?10 dB) are 17.0% (20.5‐24.3 GHz) and 15.2% (26.1‐30.4 GHz), while the measured axial ratio (AR) bandwidths (AR < 3 dB) are 12.8% (21.2‐24.1 GHz) and 5% (27.4‐28.8 GHz). In addition, the peak gain values are 5 and 8 dBic.     

LTCC‐based monolithic system‐in‐package (SiP) module for millimeter‐wave applications

A miniature LTCC system‐in‐package (SiP) module has been presented for millimeter‐wave applications. A typical heterodyne 61 GHz transmitter (Tx) has been designed and fabricated in a type of the SiP module as small as 36 × 12 × 0.9 mm³. Five active chips including a mixer, driver amplifier, power amplifier, and two frequency multipliers were mounted on the single LTCC package substrate, in which all passive circuits such as a stripline (SL) BPF, 2 × 2 array patch antenna, surface‐mount technology (SMT) pads, and intermediate frequency (IF) feeding lines have been monolithically embedded by using vertical and planar transitions. The embedded SL BPF shows the center frequency of 60.8 GHz, BW of 4.1%, and insertion loss of 3.74 dB. The gain and 3‐dB beam width of the fabricated 2 × 2 array patch antenna are 7 dBi and 36 degrees, respectively. The assembled LTCC 61 GHz Tx SiP module achieves an output power of 10.2 dBm and an up‐conversion gain of 7.3 dB. Because of the integrated BPF, an isolation level between a local oscillation (LO) and RF signal is below 26.4 dBc and the spurious level is suppressed by lower than 22.4 dBc. By using a 61 GHz receiver (Rx) consisting of off‐the‐shelf modules, wireless communication test was demonstrated by comparing measured IF spectrums at the Tx and Rx part.     

A miniaturized ultra‐wideband planar monopole antenna with L‐shaped ground plane stubs

This article presents a miniaturized ultra‐wideband planar monopole antenna with an oval radiator. The proposed antenna is fed by a coplanar waveguide (CPW), and two L‐shaped stubs are extended from the ground plane of the CPW. This presented antenna is able to produce resonances in the lower frequency band and realize better impedance matching performance in the middle and higher frequency bands with the aid of the L‐shaped stubs. The antenna was built and tested. The total size of the proposed antenna is only 26 × 20 × 1.6 mm³. Its measured –10 dB impedance bandwidth is 10.1 GHz (3.1‐13.2 GHz). The measured far‐field radiation patterns are stable in the whole operating frequency band.     

A low volume flexible CPW‐fed elliptical‐ring with split‐triangular patch dual‐band antenna

In this article, the intensive investigations are carried out on a low volume compact flexible antenna for wireless applications with a novel structure model. The proposed model has considered as an elliptical‐ring with split‐triangular patch (ERSTP) antenna with the coplanar waveguide feeding to achieve dual‐bands. The ERSTP antenna is designed with polyimide material having the volume (L _a × W _a × h) 99 mm³. The ERSTP antenna resonates with 2.60 GHz and 3.48 GHz frequencies with a reflection coefficient of ?21.92 dB and ?32.14 dB and a gain of 2.39 dBi and 1.75, dBi respectively. The impedance bandwidths are 100 MHz and 330 MHz observed at two frequency bands. The proposed ERSTP antenna has operated on mobile‐worldwide interoperability for microwave access (M‐WiMAX) and worldwide interoperability for microwave access (WiMAX) bands respectively. The simulated and measured results of ERSTP antenna are in good agreement.     

Performance comparison of a single and multiband power amplifiers using IHP 0.25 μm SIGe HBT technology

In this work, a single‐band power amplifier (PA) with a fixed‐frequency/band output matching network and multiband PA with a switch‐tuned output matching network is designed, using IHP (Innovations for High Performance), 0.25 μm‐SiGe HBT process. The behavior of the amplifiers has been optimized for 2.4 GHz (WLAN), 3.6 GHz (UWB‐WiMAX), and 5.4 GHz (WLAN) frequency bands for a higher 1‐dB compression point and efficiency. Multiband characteristics of the amplifier were obtained by using a MOS‐based switching network. Two MOS switches were used for tuning the band of the output matching network. Postlayout simulations of the multiband‐PA provided the following performance parameters: 1‐dB compression point of 25.2 dBm, gain value of 36 dB, efficiency value of 12.8% operation and maximum output power of 26.8 dBm for the 2.4 GHz WLAN band, 1‐dB compression point of 25.5 dBm, gain value of 32 dB, efficiency value of 13.3% and maximum output power of 26.6 dBm for the 3.6 GHz UWB‐WiMAX band and 1‐dB compression point of 24.8 dBm, gain value of 23 dB, efficiency value of 12.5% and maximum output power of 26.3 dBm for the 5.4 GHz WLAN band. For the fixed‐band, at 3.6 GHz, the postlayout simulations resulted the following parameters: 1‐dB compression point of 25.5 dBm, gain value of 32 dB, efficiency value of 18% and maximum output power value of 26.8 dBm. Measurement results of the single‐band PA provided the following performance parameters: 1‐dB compression point of 20.5 dBm, gain value of 23 dB and efficiency value of 7% operation for the 2.4 GHz band; 1‐dB compression point of 25.5 dBm, gain value of 31.5 dB and efficiency value of 17.5% for the 3.6 GHz band; 1‐dB compression point of 22.4 dBm, gain value of 24.4 dB and efficiency value of 9.5% for the 5.4 GHz band. Measurement results show that using multistage topologies and implementing each parasitic as part of the matching network component has provided a wider‐band operation with higher output power levels, above 25 dBm, with SiGe:C process. These results proved that the PA, with switching/tunable output matching network, provides compatible performance parameters, when compared with the fixed‐band PA. The ability of being capable of operation in different frequency bands with compatible performance parameters, when compared with fixed‐band PA, multiband PA can be realized with additional less parasitics, area, and cost advantages. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.     

Broadband compact CPW‐fed metasurface antenna for SAR‐based portable imaging system

A broadband and compact coplanar waveguide (CPW) coupled‐fed metasurface (MS)‐based antenna for C‐band synthetic aperture radar (SAR) imaging application is proposed in this article, which is consisted of 16 uniform periodic square patches performed as radiators. The CPW feeding structure gives two following functions: (1) It excites an aperture coupling slot structure underneath the center of MS patch array. (2) It acts as a ground plane for the metasurface patch units. Different slots were investigated and eventually an hourglass‐shaped slot is applied to enhance bandwidth for imaging applications. A prototype with a dimension of 60 × 60 × 1.524 mm³ (1.1λ₀ × 1.1λ₀ × 0.03λ₀) operating at the center frequency 5.5 GHz (f₀) has been fabricated and measured to verify the design principle. This antenna has a measured impedance bandwidth of 12.4% from 5.14 to 5.82 GHz, a peak gain of 9.2 dBi and averaged gain of 7.2 dBi at broadside radiation. Microwave imaging experiments using the proposed antenna have been carried out and a good performance is achieved.     

A high efficiency inductor‐less broadband fully integrated CMOS power amplifier

This work presents the design and implementation of a novel broadband completely inductor‐less 300 MHz–2.4 GHz power amplifier (PA) in 180 nm CMOS, primarily for applications in the ultrahigh frequency (UHF) industrial scientific and medical band. This is capable of delivering up to 15.6 dBm saturated output power with an associated peak power added efficiency of 31% in measurement. Although amplifiers with higher output power have been reported, this amplifier occupies only 0.086 mm² and does not require any off chip component for its operation, even at the UHF band. It also achieves the highest power density among a similar class of PA's below 10 GHz. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:311–320, 2015.     

A miniature low‐power ultra‐wideband low noise amplifier in 0.18 μm CMOS

A 0.18‐μm CMOS low‐noise amplifier (LNA) operating over the entire ultra‐wideband (UWB) frequency range of 3.1–10.6 GHz, has been designed, fabricated, and tested. The UWB LNA achieves the measured power gain of 7.5 ± 2.5 dB, minimum input matching of ?8 dB, noise figure from 3.9 to 6.3 dB, and IIP3 from ?8 to ?1.9 dBm, while consuming only 9 mW over 3–10 GHz. It occupies only 0.55 × 0.4 mm² without RF and DC pads. The design uses only two on‐chip inductors, one of which is such small that could be replaced by a bonding wire. The gain, noise figure, and matching of the amplifier are also analyzed. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE , 2011.     

A novel compact self‐similar fractal UWB MIMO antenna

A novel compact self‐similar fractal ultra‐wideband (UWB) multiple‐input‐multiple‐output (MIMO) antenna is presented. This fractal geometry is designed by using iterated function system (IFS). Self‐similar fractal geometry is used here to achieve miniaturization and wideband performance. The self‐similarity dimension of proposed fractal geometry is 1.79, which is a fractional dimension. The antenna consists of two novel self‐similar fractal monopole‐antenna elements and their metallic area is minimized by 29.68% at second iteration. A ground stub of T‐shape with vertical slot enhances isolation and impedance bandwidth of proposed MIMO antenna. This antenna has a compact dimension of 24 × 32 mm² and impedance bandwidth (S₁₁ < ?10 dB) of 9.4 GHz ranging from 3.1 to 12.5 GHz with an isolation better than 16 dB. The various diversity performance parameters are also determined. There is good agreement between measured and simulated results, which confirms that the proposed antenna is acceptable for UWB applications.