The auxiliary envelope tracking RF power amplifier system

The advancement of the mobile communication industry increases the need for RF power amplifier (RFPA) to be more efficient and linear. The communication network that is shifting towards smaller micro-cell or nano-cell network has also motivated the design of the RF power amplifier to be simple, compact and cost efficient. In this research work, a novel technique for efficiency and linearity improvement of the RFPA is presented. A simplistic approach in the technique called ‘Auxiliary Envelope Tracking' (AET) system has promoted the design for small and straightforward AET tracking generator, a key component in the system. The use of low cost components in the AET tracking generator has made the technique commercially attractive. The AET technique proposes a separation in generating DC and AC components of the AET signal that biases the drain of the RFPA. The separation eases the generation of the signals resulting in low power consumption that leads to efficiency improvement. The investigation of the gain characteristic of gallium nitride (GaN) RFPA has shown an important RFPA attribute where the gain varied substantially as the drain voltage increases. By using the AET technique, the gain characteristic is harnessed to get linearity improvement. In order to validate the technique, AET measurement systems for two-carrier and WCDMA signals were developed and experimented. A special Class AB RFPA is designed and implemented to use dedicatedly for this investigation. In two-carrier signal measurement, a tracking generator is developed that consists of an envelope amplifier (EA) and a diplexer. The RFPA and the tracking generator are then combined to be an integrated AET block. In order to accommodate the high peak-toaverage ratio (PAR) and high bandwidth WCDMA signal, a broadband RF transformer was designed as part of the AET tracking generator to replace the diplexer. The two-carrier and WCDMA signals measurement results have proven that the AET technique is a valid technique for efficiency and linearity improvement. The improvements were achieved with simple, compact and cost-effective implementation.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

The auxiliary envelope tracking RF power amplifier system

The advancement of the mobile communication industry increases the need for RF power amplifier (RFPA) to be more efficient and linear. The communication network that is shifting towards smaller micro-cell or nano-cell network has also motivated the design of the RF power amplifier to be simple, compact and cost efficient. In this research work, a novel technique for efficiency and linearity improvement of the RFPA is presented. A simplistic approach in the technique called ‘Auxiliary Envelope Tracking' (AET) system has promoted the design for small and straightforward AET tracking generator, a key component in the system. The use of low cost components in the AET tracking generator has made the technique commercially attractive. The AET technique proposes a separation in generating DC and AC components of the AET signal that biases the drain of the RFPA. The separation eases the generation of the signals resulting in low power consumption that leads to efficiency improvement. The investigation of the gain characteristic of gallium nitride (GaN) RFPA has shown an important RFPA attribute where the gain varied substantially as the drain voltage increases. By using the AET technique, the gain characteristic is harnessed to get linearity improvement. In order to validate the technique, AET measurement systems for two-carrier and WCDMA signals were developed and experimented. A special Class AB RFPA is designed and implemented to use dedicatedly for this investigation. In two-carrier signal measurement, a tracking generator is developed that consists of an envelope amplifier (EA) and a diplexer. The RFPA and the tracking generator are then combined to be an integrated AET block. In order to accommodate the high peak-toaverage ratio (PAR) and high bandwidth WCDMA signal, a broadband RF transformer was designed as part of the AET tracking generator to replace the diplexer. The two-carrier and WCDMA signals measurement results have proven that the AET technique is a valid technique for efficiency and linearity improvement. The improvements were achieved with simple, compact and cost-effective implementation

Design of a 1.9 GHz low-power LFSR circuit using the Reed-Solomon algorithm for Pseudo-Random Test Pattern Generation

A linear feedback shift register (LFSR) has been frequently used in the Built-in Self-Test (BIST) designs for the pseudo-random test pattern generation. The volume of the test patterns and test power dissipation are the key features in the large complex designs. The objective of this paper is to propose a new LFSR circuit based on the proposed Reed-Solomon (RS) algorithm. The RS algorithm is created by considering the factors of the maximum length test pattern with a minimum distance over the time. Also, it has achieved an effective generation of test patterns over a stage of complexity order O (m log2 m), where m denotes the total number of message bits. We analyzed our RS LFSR mathematically using the feedback polynomial function for an area-sensitive design. However, the bit-wise stages of the proposed RS LFSR are simulated using the TSMC 130 nm IC design tool in the Mentor Graphics platform. Experimental results showed that the proposed LFSR achieved the effective pseudo-random test patterns with a low-test power dissipation (25.13 µW). Ultimately, the circuit has operated in the highest operating frequency (1.9 GHz) environment.   &nbsp

Multibeam Array Antenna with Compact Size Butler Matrix for Millimeter-Wave Application

New radio wave technologies of millimeter-wave (mmWave), compact cell size, and multi beam base station are introduced with the recent development of the 5G mobile system. The Butler Matrix (BM) feed circuit is the most preferable candidate for the 5G mobile system since it can achieve multi beam radiation patterns at the array antenna, provide structural compactness and produce good multi beams. The BM circuit is typically built on a single dielectric substrate. However, in this single-substrate structure, the micro strip line connecting several circuit elements in the BM spans over a large area, resulting in significant feeding loss in the millimeter frequency band. In this study, a compact size circuit configuration of BM is proposed, where the original single-substrate structure is modified into a two-substrate stacking structure. The via-hole is designed to connect the two substrates with minimal path loss. The BM is built for the 28 GHz band with four inputs and four outputs. The phase delay is optimized using via-hole to produce the phase difference of ±45º and ±135º. The coupling for the hybrid is -3 dB, while the transmission coefficient of -6 ± 3 is achieved from the BM structure and, the return loss (Sii) for both input and output ports are less than -10 dB. The two-substrate BM is combined with the rectangular patch antenna and the via-hole patch antenna in a planar configuration of 0.5 λ0 spacing to obtain the radiation patterns. When the Port 1 through Port 4 of the BM are fed, four beams are created, with peak gains of 11.2 dBi, 9.87 dBi, 10.2 dBi, and 11.7 dBi, respectively, towards +16°, -35°, +39°, and -12°. The analysis includes the radiation performance from the ideal value and from the BM input. Three-dimensional representations of good multibeam radiation patterns are obtained after each input signal of the BM is fed

Multibeam Array Antenna with Compact Size Butler Matrix for Millimeter-Wave Application

New radio wave technologies of millimeter-wave (mmWave), compact cell size, and multi beam base station are introduced with the recent development of the 5G mobile system. The Butler Matrix (BM) feed circuit is the most preferable candidate for the 5G mobile system since it can achieve multi beam radiation patterns at the array antenna, provide structural compactness and produce good multi beams. The BM circuit is typically built on a single dielectric substrate. However, in this single-substrate structure, the micro strip line connecting several circuit elements in the BM spans over a large area, resulting in significant feeding loss in the millimeter frequency band. In this study, a compact size circuit configuration of BM is proposed, where the original single-substrate structure is modified into a two-substrate stacking structure. The via-hole is designed to connect the two substrates with minimal path loss. The BM is built for the 28 GHz band with four inputs and four outputs. The phase delay is optimized using via-hole to produce the phase difference of ±45º and ±135º. The coupling for the hybrid is -3 dB, while the transmission coefficient of -6 ± 3 is achieved from the BM structure and, the return loss (Sii) for both input and output ports are less than -10 dB. The two-substrate BM is combined with the rectangular patch antenna and the via-hole patch antenna in a planar configuration of 0.5 λ0 spacing to obtain the radiation patterns. When the Port 1 through Port 4 of the BM are fed, four beams are created, with peak gains of 11.2 dBi, 9.87 dBi, 10.2 dBi, and 11.7 dBi, respectively, towards +16°, -35°, +39°, and -12°. The analysis includes the radiation performance from the ideal value and from the BM input. Three-dimensional representations of good multibeam radiation patterns are obtained after each input signal of the BM is fed

0.5 GHz-1.5 GHz Bandwidth 10W GaN HEMT RF Power Amplifier Design

With the current development in wireless communication technology, the need for a wide bandwith in RF power amplifier (RF PA) is an essential. In this paper, the design and simulation of 10W GaN HEMT wideband RF PA will be presented. The Source-Pull and Load-Pull technique was used to design the input and output matching network of the RF PA. From the simulation, the RF PA achieved a flat gain between 15dB to 17dB from 0.5GHz to 1.5GHz. At 1.5GHz, the drain efficiency is simulated to achieve 36% at the output power of 40 dBm while the power added efficiency (PAE) was found to be 28.2%

5G beam-steering 2×2 butler matrix with slotted waveguide antenna array

In this research paper, substrate integrated waveguide (SIW) was proposed as a technique by realizing bilateral edge walls to produce a compact 5G beam-steering antenna at 24 GHz. The beam forming network is produced using SIW directional coupler perform as 2×2 Butler Matrix (BM) fed with SIW slotted waveguide antenna array. The output signal is steered from -29 degrees and +29 degrees when the signal is fed to the respective input ports. If one of the input ports is fed, the signal is evenly distributed between the adjacent output ports with 90 degree constant phase shift. The compact size of directional coupler was designed by longitude slots on the surface of SIW substrate with bandwith of 16.85% at the operating frequency. The proposed antenna produce gain of 6.34 dB at operating frequency and the promising outcome of the beam steering make proposed design suitable for 5G communications especially with tracking capabilities

Effect of operating temperature on direct recycling aluminium chips (AA6061) in hot press forging process

A method of solid-state recycling aluminum alloy using hot press forging process was studied as well as the possibility of the recycled chip to be used as secondary resources. This paper presents the results of recycled AA6061 aluminium alloy chip using different operating temperature for hot press forging process. Mechanical properties and microstructure of the recycled specimens and as-received (reference) specimen were investigated. The recycled specimens exhibit a good potential in the strength properties. The result for yield strength (YS) and ultimate tensile strength (UTS) at the minimum temperature 430˚C is 25.8 MPa and 27.13 MPa. For the maximum operating temperature 520˚C YS and UTS are 107.0MPa and 117.53 MPa. Analysis for different operating temperatures shows that the higher temperatures giving better result on mechanical properties and finer microstructure. The strength of recycled specimen increases due to the grain refinement strengthening whereas particle dispersion strengthening has minor effects. In this study, the recycled AA6061 chip shows the good potential in strengthening as the comparison of using only 17.5% of suggested pressure (70.0/400.0) MPa, the UTS exhibit 35.8% (117.58/327.69) MPa. This shows a remarkable potential of direct recycling by using hot press forging process

Wireless power transfer with on-chip inductor and class-E power amplifier for implant medical device applications

The popular use of biomedical implants has been going on in numerous applications that include the use of pacemakers and emerging retina prostheses, together with brain-computer interfaces. Other popular uses include drug delivery and smart orthopaedic implants. The avoidance of batteries or piercing wirings has made the wireless powering of these implantable devices highly attractive. In this paper, a design of a class-E power amplifier which has inductive loading appropriate for implant application was made using 130nm Silterra CMOS process at 2.4V supply. A presentation of high-Q on-chip inductors is made as a way of improving the efficiency of the wireless power transfer (WPT) system at 37.5MHz industrial, scientific and medical (ISM) band. Wireless power transfer efficiency of 59-89% is obtained for distance variation up to 10mm of the implant coil from the transmit power coil. DC voltage of more 3V is obtained for distance up to 10mm of the implant coil; and the on-chip implant inductor measures a smaller size of 10mm×10mm making the design more suitable for the application of medical implant

Multimode multiband power amplifier with tapped transformer for efficiency enhancement in low power mode

Multimode multiband connectivity has become a defacto requirement for smartphones with 3G WCDMA/4G LTE applications. In this research, a two-stage multimode multiband (MMMB) power amplifier (PA) with multiple gated transistor (MGTR) and configurable tapped transformer is designed and analysed in view of enhancing the efficiency in low power mode. The designed MMMB PA offers a 900MHz of operating bandwidth starting from the frequency of 1400MHz up to 2300MHz, covering 16 LTE FDD bands with peak output power of 27.8dBm and peak PAE of 31% in the high power mode. In low power mode, the PA offers the same bandwidth with peak output power of 25.5dBm and PAE of 30%. Use of the multiple gated transistor with tapped transformer for matching has increased the PAE in low power mode by 19% compared with that PAE in the high power mode