Cross Talk Minimization. The trace impedance (single-ended) in an individual trace is normally calculated by ignoring any neighboring traces, so no coupling to other conductors in the design will. Parameterized Design - Differential Lines: This example shows a typical parameterized differential microstrip transmission line design in EMPro. That means on ten mil (254 micron). Broadband stacked shorted patch antenna for mobile communication handsets. This impedance is defined between the track and GND plane (microstrip) or between two tracks (differential microstrip pair) or between two tracks with GND plane (3 conductor differential pair). 3. Fifth, it provides application examples of differential antennas from simple discrete wire to sophisticated microstrip designs. for differential operation than the microstrip patch antenna [4]–[8], due to its origin from the single-ended monopole. This article presents a magnetless differential microstrip circulator for high frequency operation. What is more, the STM biases of the two SE. The notation of Sdd31 is defined as the gain ratio of induced voltage at port 3 (victim's input. resonator for differential-fed BPFs. The edge couple differential symmetric stripline transmission line is a common technique for routing differential traces. Cross Talk Minimization. These modes maybepresent inthedifferential line simultaneously, whichmeans that these lines propagate hybrid even- and odd-mode waves. The antenna is composed of the main patch, the short-end parasitic patch, and the matching network. The differential line model consists of two single microstrip lines printed on a substrate with a permittivity value of 3. e. 3 shall be used. This is a hobby project and the. Figure 5. Much has been written about terminating PCB traces in their characteristic impedance, to avoid signal reflections. The dipole antenna with semi-elliptic arms is introduced to transform the. Therefore, it is interesting to design the differential transition structure between differential SIW and microstrip lines. A 45 degree differential microstrip phase shifter operating in the frequency band ranging from 1. The sensor shows a single transmission zero, when it is unloaded or loaded symmetrically on both halves. The differential design is obtained by pairing two single-ended (SE) circulators, each based on. So I decided to try and verify the calculator - jlcpcb offer an impedance calculator in their quotation system, and for a 6-layer 1. If the surface layer ground pours in the above image are too close to the trace, then we have a coplanar waveguide, not a microstrip. Due to these advantages over. A balanced pair of microstrip lines is a convenient solution because it does not need an additional PCB layer, as a stripline does. A differential microstrip transmission line is constructed with two traces on the same reference plane. It is not easy to change from one to another. There are generally longer. Dielectric Thickness (h) Dielectric Constant (εr) Calculate. A study of the surface waves excited by the. In addition, the slot’s length is enlarged to decrease. I made a simplified geometry of my actual resonator. Before using these scales, the characteristic im-pedance Z0, of the individual conductor must first be found using the Microstrip and Stripline Z0 scales on Side Two. This article presents a magnetless differential microstrip circulator for high frequency operation. 4. 9 to 1. There are four types of impedance used in characterizing. The surface roughness of the conductor. 15 mm spacing. A symmetrical stripline is shown in Figure [Math Processing Error] 3. a simple microstrip. 18 μm CMOS technology. Just to give designers a starting point, take a look at these differential impedance calculators you can use to get an initial estimate of the differential impedance for microstrips and striplines. 5 dBi at the center frequency and. Several people have developed procedures that can be used to synthesize microstrip lines. The edge couple differential symmetric stripline transmission line is a common technique for routing differential traces. 7 GHz is presented in this paper. This is based on antipodal finlines and Vivaldi-like antennas on an ultrathin liquid crystal polymer substrate inserted in a WR10. a simple microstrip. The sensor consists of a splitter/combiner section with two symmetrical complementary split-ring resonators (CSRR). – Microstrip lines are either on the top or bottom layer of a PCB. The compact rat-race coupler and an 180 0 hybrid junction, provide the differential signal to the inverted microstrip patch. All the elements are vertically integrated without increasing the dimensions. The analysis of this particle as well as the potential applications in microstrip configuration, is the main objective of the present work. 46 mm width traces to obtain 100 Ohms ZDiff while using 0. pled from the conductors to the ground planes. Another consequence is the following: If you densely route several single-ended lines, I suggest you throw the values into a differential line calculator. Differential Microstrip Impedance. By understanding the microstrip transmission line, designers can. 5 dBi at the center frequency and. 5 dBi at the center frequency and exhibits VSWR ≤ 2 for frequencies between 870 MHz to 1. DOI: 10. A good guideline to determine when the transmission line approach is necessary for logic signals The edge coupled differential microstrip transmission line is a common technique for routing differential traces. In this paper, a co-design of differential filtering antenna is presented in Fig. A study of the surface waves excited by the. To realise the tri-mode BPF performance, the multimode stepped-impedance resonator is introduced and parallel coupled to both the balanced and the unbalanced ports. The instantaneous differential impedance is related to the voltage simulated at the V_TDR node from: A generic cross section of a microstrip differential pair is shown in Figure 2. Typically, a long and a short circuit are used, with the difference in length a ratio of 3:1 or greater as. Differential/common mode using an odd/even mode analysis is used to calculate the operating frequency of the circuit. IEEE Sensors Journal 2022-10-15 | Journal article. Differential feeding methods have been studied in literature to suppress cross-polarized fields in MPAs [34,58]. A partial differential equation is obtained from the model which is solved using “Reduced Differential Transformation Method (RDTM)”. For example, if u = 1 and ε r = 10, then from the figure, Z 0 ε e = 126 Ω. Differential Impedance Ω. Because the differential impedance for symmetrical lines is equal to twice the odd-mode impedance, this measurement translates to an equivalent differential impedance of 85 Ω . This calculator finds both odd and even transmission line impedance. To use this calculator, simply input your microstrip geometry and Dk value, and the tool will return the differential impedance value for a pair of microstrip traces. D = Distance between two differential pair signals; W = Width of a trace in a. It also causes the characteristic impedance to be frequency dependent. Also, the upper and lower microstrip lines are connected by copper pin with radius r which goes. As the bandpass filter is the widely used filter in the transmitter and receivers in communication systems, the design of metamaterial-based microwave. Differential circuits are often employed in the integrated high speed circuit designs with the virtues of noise immunity, harmonic suppression, and large dynamic range [1,2,3]. I've added a label (EG) to what I think you are asking about, which would effectively be the "external gap" between differential pairs: The short answer is: make the external gap 5 times as wide as the trace width of one of the traces in the differential pair. The differential characteristic impedances of the differential microstrip, stripline and via stub are 100, 100 and 72 Ω. One of the features of this type of microstrip is the coupling between lines. Microstrip lines have a quasi-TEM mode of propagation, making it easy to realize various lumped-elements. This paper presents a microwave sensor using a pair of split-ring resonators (SRRs). Fifth, it provides application examples of differential antennas from simple discrete wire to sophisticated microstrip designs. 2 of the Microstrip Calculator, h=H1 and b=H2-H1. A differential stripline pair refers to two traces located between two reference plane layers, which are routed as a. A differential line is composed of two transmission lines excited by two out-of-phase signals. You can rename differential pair objects on the PCB. 3. In a differential serpentine delay microstrip line (DSDML), the main contributions to commonmode noise originate from the length mismatch of the verticalturn-coupled traces (VTCTs), the length of. – Striplines are embedded between two reference layers, which results in a higher capacitance versus microstrip lines. Differential surface coplanar waveguide with ground calculations: *0. Incidentally, the trace thickness parameter does have a significant effect. For the odd mode, the differential impedance can be obtained by setting the. CPS stand for Coplanar. The tapered transition is only 8. There are generally longer. 2 of the Microstrip Calculator, h=H1 and b=H2-H1. This impedance is not the characteristic impedance of the. 5 GHz. Distinct from conventional single-ended patch antennas, the DMPA uses a pair. Four dual-strip structures connected with the feeding probes are placed below the driven patch to. Therefore, in order to meet the increasing demands for multifunctional systems in the recent wireless applications such as 4G and 5G systems, differential-fed. The designs are presented and the performance of the transitions is evaluated in simulation and measurements. In thi spaper, two millimeter-wave transitions from dielectric rectangular waveguide (DWG) to Microstrip line (MSL) are designed at V-band (50-75GHz) for contactless excitations using the. I have assigned PerfE boundaries to each trace and pad element in yellow. A new method is suggested whereby interconnect. The microstrip impedance represents the characteristic impedance of the microstrip line. 6. Microstrip Impedance Calculator. 15 mm spacing. For differential circuits, two conductors are used. Overview. 29 mm width traces to obtain 100 Ohms ZDiff while using 0. First, the design formulas to determine the patch dimensions and the location of the feed point for single-ended microstrip antennas are examined to design differentially-driven microstrip antennas. This calculator finds both odd and even transmission line impedance. Figure 5. You can use this transmission line to connect two PCB components or to create components such as filters, couplers, and feeding. Coplanar waveguides, striplines, and microstrip traces that require impedance control all need to be sized such that the width produces the desired characteristic impedance. While this calculator will provide a baseline, any final design considerations should be made towards loss, dispersion, copper roughness, phase shift, etc. This antenna consists of a differential-fed microstrip patch, a U-shaped differential resonator, and two pairs of quarter-wavelength J-inverters. 75 psTr Forward crosstalk design limit for crosstalk depends on signal risetime. Finally, a comparison of differential dual-polarisation microstrip patch antennas is given in Table 2. Using Saturn's PCB Toolkit, it seems to be extremely difficult to achieve 100R. My layer stackup is Signal-GND-Power-Signal. 1109/LMWC. The differential microstrip line comprises of two copper traces and a dielectric substrate enclosed in. Microstrip Impedance Calculator. These antennas have many advantages like low profile, low cost,. A 22 microstrip antennas array is used as a test case to corroborate the efficacy of the proposed scheme. 671; thus Z 0 = 48. Choose Type. ) parameters and the complex propagation. 3 gives differential multilayer microstrip transition structure which has three dielectric layers and four metal layers. It is shown that the impedance of a differential feed antenna exhibits cosine squared behavior over the feed distance. A Dielectric Sensor Based on Differential Microstrip Lines Coupled With Multiple Magnetic-LC Resonators. The antenna has a segmented feed line, a rectangular driven patch etched with a double I-slot, and a squared stacked patch with grooves at the edges of both sides. proposed for differentially-driven microstrip antennas to improve impedance bandwidth. In the proposed antenna, the driven patch operates in a TM10 mode with an inherent radiation null caused by a higher mode TM12. In the proposed antenna, the driven patch operates in a TM10 mode with an inherent radiation null caused by a higher mode TM12. Visit to learn more about the EEWeb communit. A differential microstrip antenna with improved gain for RF energy harvesting is presented in this paper. It mentions formula or equations used in this differential Microstrip Impedance Calculator. This page covers Differential Microstrip Impedance Calculator . 6mm board, 100R microstrip differential impedance, they suggest 4/5 mil trace/space, which is a bit different than 9/4. It has been shown that, compared with conventional differential microstrip lines, the CSPs can be strongly confined in the grooves of the corrugated microstrip lines, so the crosstalk between the. 4 µm. Edge-coupled coated differential microstrip Edge coupled differential microstrip for flex PCB. Match the etch lengths of the relevant differential pair traces. Proper routing and layer stack-up through microstrip and stripline layouts can minimize crosstalk. 3 V, etc. 12. J. The formulas are useful outside the range indicated, but with reduced accuracy. These parameters include:Microstrip is the most popular medium for circuit design at frequencies ranging from several hundred megahertz to tens of gigahertz. Basically the single-ended microstrip impedance in differential pair calculators is a fake value, and half the differential pair value would be the actual single-ended impedance. The differential skew is adjusted with a tiny blip on one line towards the bottom of this image. Example. ground plane, consist of two strip of copper over a substrate. As we know theoretically there would be two same signals with 180 phase. The simulated results based on full-wave simulator will provide a good reference for the design of differential coupled microstrip lines over LPC-EBG power/ground planes. Based on a quarter-wavelength resonator, a new PCB filter is designed having an electrical size of only 0. 55 Ω . The presented antenna mainly consists of. The simulation shows insertion loss for 1". The proposed antenna consists of 2 orthogonal microstrip grid array and four parasitic patches. The input impedance, Zin, of the shorted microstrip line is shown in Figure 3. For this frequency range, to the authors’ knowledge, it is the first time that a fully differential microstrip antenna/array is presented. The sensor is easily implemented on an affordable substrate FR-4. The impact on computed S-parameters due to a fictitious noise source is demonstrated for each microstrip line configuration, respectively. Single-ended signals are fairly straightforward. Hello, I want to simulate a differential pair that is capacitively coupled to a microstrip pair. The calculated, simulated and measured results are in good agreement with each other. example. But such thin traces present a problem in achieving 100Ω differential impedance (on a differential microstrip). A stripline resembles a microstrip line and comprises a center conductor pattern symmetrically embedded completely within a dielectric, the top and bottom layers of which are conducting ground planes. Wire Microstrip Impedance Calculator. There are generally longer. PCB Microstrip is a commonly used type of electrical transmission line for conveying microwave-frequency signals. A variant on this is a different coplanar waveguide with ground. The microstrip transmission line is aligned with. Two configurations are studied, the first one without the inset feed point (Fig. 2019. The center tap of the isolated winding has “Bob Smith” termination through a 75 ohm resistor and a 1000 pF cap to. 1109/JSEN. Going to a coplanar arrangement can provide more losses when the coplanar ground is close, which forces a thinner microstrip (more loss from skin effect). 6 mm 0. A novel differential microstrip patch antenna (DMPA) is designed for autonomous cruise control radar systems at 79 GHz. A differential microstrip antenna with improved gain for RF energy harvesting is presented in this paper. There is no GND plane in this model, the wires act as reference and do not receive direct excitation. The conducting plane is assumed to be an ideal ground with equal potential all over the plane. The two arms of the dipole antenna are connected together by a shorting strip to reduce the size of the dipole. Again, these formulas are the result of curve fits, but starting with physically. It eliminates the need of a balun in the RF frontend and supports the realization of more compact radar frontend. At resonance, the transmission line experiences a matched load causing a reflection zero. Novel resistor-free differential microstrip lines prototype loaded with lossy metamaterial is proposed to achieve wideband common-mode (CM) absorption. The design of a novel differential shorted patch antenna (DSPA) from a normal single-ended shorted patch antenna (SPA) is presented. 2014a). So how to define these two opposite ports and how to see the results ( differential impedance i. Intra-pair skew is the term used to define the difference between the etch length of the + and - lane of a differential pair. attenuation than the commonly used microstrip but have added complexity in introducing the signal to the transmission line in a PCB environment. 19 dBm at 980 MHz. 38λ. The cavity-mode theory and the dyadic Green's function. Note: valid. 2. This property of the microstrip line can be extended to coupled microstrip lines and applied to compensate for time skew in right-angle bent differential lines. On the PCB side, each resulting differential pair object will be added to the default Differential Pair class: <All Differential Pairs>. The transition was designed at. LVDS pairs need 100 ohms differential impedance. For a differential microstrip circuit, for example, the E fields would be coupled between two signal conductors on the top layer and the ground plane below. Cross-section geometry of a stripline trace. The proposed microstrip sensor is evolved from a traditional microstrip sensor, which has a single resonator unit excited by a single microstrip line. This letter presents a vertically integrated differential filtering antenna. Show more detail. There are four different types of impedance used in characterizing differential trace impedances. While commonly constructed using printed circuit boards, this structure can also be built using other materials as long as there is a conductor separated from. Two W-band inline transitions between microstrip line and rectangular waveguide are presented. Figure 16. Ideally the traces in the differential pair only interact with each other, as another answer said. 2. 4 GHz and 5. Target Impedance (Z0) Trace Thickness (t) mils. Matching the differential trace length and keeping the distances between the traces consistent is a common practice. The transition was designed at 75 GHz,. A cross section of microstrip is shown in Figure 1. (b) Equivalent circuit model of the sensor. Because each line causes a matching image current in the ground plane, which is required anyway for. Microstrip Impedance Calculator. 250 mil Length 35 –8. Posted on July 21, 2012 4:09 am by Cody MillerA differential microstrip patch antenna (DMPA) inside the waveguide acts as a radiation element. This is a slot resonator that can be etched in the ground plane of a single-ended microstrip or a differential microstrip line. – Microstrip lines are either on the top or bottom layer of a PCB. Differential Via Figure 1 shows the construction of a typical differential via in a high-speed serial link. It is shown that the DSPA has a smaller. 250 mil Length 35 –8. Thus, the coupon length can be significantly reduced. U. It converts the initial differential step edge signal into the individual p and n signals used to excite the p and n lines of the differential pair. Differential surface coplanar waveguide with ground calculations: *0. This provides common-mode noise cancellation in addition to isolation from other circuit blocks in an RF system. Microstrip construction consists of a differential pair and a single reference layer (typically ground). The circuits should be identical in every way except physical length. Microstrip lines, coplanar waveguides. The closer you place the pairs together, the differential impedance gets smaller because LM and CM get larger. The antenna has a gain of 8. Useful converters and calculators. 5. That said, microstrip is marginally easier to deal with to meet the correct impedance since the trace will be fatter. Edge Coupled Microstrip Differential Impedance Calculator. 01450Microstrip Differential Impedance is a key parameter in the design of high-speed digital and high-frequency analog circuits. Figure 1. The sensing area contains two pairs of open-This property of the microstrip line can be extended to coupled microstrip lines and applied to compensate for time skew in right-angle bent differential lines. Following is the list of useful converters and calculators. High-frequency circuit designers must often consider the performance limits, physical dimensions, and even the power levels of a particular design when deciding upon an optimum printed-circuit-board (PCB) material for that design. Using this property, the TDT times of. Edge Coupled Microstrip. freedom in differential microstrip lines are enough to simulta-neously achieve line impedance modulation for the common mode and a uniform characteristic impedance for the dif-ferential mode. Routing Differential Microstrip Traces with Controlled Impedance Differential microstrip routing in high speed PCB design requires careful impedance calculations. Sorted by: 1. Microstrip to waveguide transitions used presently typically require a relatively complex waveguide mount extending on both sides of the planar circuit. Transmission-line models are used to analyze differential- and. Design of low phase noise K‐band VCO using high quality factor resonator in 0. There will be some slight coupling of the signal onto the adjacent grounds, so they should be adequately grounded by vias to the microstrip ground, at least every λ/10, to prevent coupling into structures that. It is good practice to match differential trace length and to keep the distances between the. Using the minimum trace spacing of 76. Inter-pair skew is used to describe the difference between the etch lengths of a differential pair from another differential pair of the same group. DOI: 10. However, in many of these 3D circuits and packages, a finite width ground plane is used to enable higher levels of. Differential Microstrip Impedance. 2mil s e=4 m s s microstrip stripline v mw s r p r a r v l m l s ab Fig. This subject is considered in much more depth in [4], and here just one approach is reported. , often all on the same PCB. Use the microstripLineCustom object to create a coupled form of single or differential microstrip transmission line. The antenna has a gain of 8. Differential-fed filters [20,21], differential-fed power dividers [22,23], and differential-fed antennas [24,25,26] are the most widely used differentially driven microstrip devices. Dimensional units: mm mils Zo (single ended impedance, Ohms) = d (trace separation) = h (dielectric thickness) = Zd (Impedance, Ohms) = Differential Stripline Impedance. 0 Dimensional units: mm mils w (trace width) = d (trace separation) = This calculator is designed to calculate the characteristic impedance of a microstrip - a flat conductor suspended over a ground plane with a dielectric between them (see diagram below). They cover the single-ended and equivalent differential microstrip line case and result from a common design procedure. For example, if u = 1 and ε r = 10, then from the figure, Z 0 ε e = 126 Ω and ε e / ε r = 0. Most of differential circuits have been constructed with conventional planar transmission lines (T-lines) such as microstrip and coplanar waveguide (CPW) and only few is concerned with plasmonic T. The traditional synthesis procedure of bandpass. Differential Trace Routing. 8), the ratio of W/H for fifty-ohm microstrip is about 95%. 42131B−WIRELESS−05/2013A microstrip highly sensitive differential sensor for complex permittivity characterization of urine samples was designed, fabricated and tested. With t = 35 um (typical for copper with plating on a pcb), Z odd drops to 44 ohms, according to LineCalc. A new differential feeding scheme and two parasitic patches are adopted to improve the impedance bandwidth of SF-MGAA. But practically (especially in a dense design like your example), they also interact with surrounding conductors, and the coplanar ground, or ground beneath a differential microstrip will affect the characteristic impedance. A four port two stage branch-line differential-mode BPF is first designed. The microstrip and stripline structures are available for free to any visitor after a brief registration. A wideband differential-fed microstrip patch antenna based on radiation of three resonant modes of TM<sub>12</sub>, TM<sub>30</sub>, and slot is proposed in this paper. Read more. where Z 0,surf can be computed as specified in Eq. 7. Fig. It is mainly . J. But the choice of transmission-line technology, such as microstrip or grounded coplanar waveguide. A differential microstrip lines-based microwave microstrip sensor loaded with multiple magnetic-LC (MLC) resonators is proposed in this manuscript. Routing Differential Microstrip Traces with Controlled Impedance Differential microstrip routing in high speed PCB design requires careful. A differential stripline pair refers to two traces located between two reference plane layers, which are routed as a differential pair. A power divider is a three-port microwave device that is used for power division or power combining. The differential topology is applied more and more in microwave and millimeter-wave circuits, for its high immunity to crosstalk and noise. A novel differential microstrip patch antenna (DMPA) is designed for autonomous cruise control radar systems at 79 GHz. 11. The Sierra Circuits Impedance Calculator uses the 2D numerical solution of Maxwell’s equations for PCB transmission lines. Two symmetrical trapezoid-shaped slots and four triangle-cut corners on the ground are used to improve the impedance matching over the UWB. To maximize signal integrity, proper routing techniques for differential signals are important for high-speed designs. Single-Ended Impedance. It is good practice to match differential trace length and to keep the distances. In the most basic sense, hatching works just like any other ground plane. I am a new user to ADS. First: there is not such thing "differential microstrip". 5. 8. Crosstalk is the unwanted coupling of signals between parallel traces. Differential impedance is twice the odd mode impedance. 3 shall be used. PCB Differential Broadside Coupled Stripline Impedance Calculator. MICROSTRIP WIDTH CALCULATOR. Thus, a compact 1 × 4 differential SIW slot antenna array with high CM rejection can be designed using the differential microstrip transition structure which has little conversion between differential-mode (DM) and CM. Differential microstrip stackup & dimensions (in microns). 6. A microstrip line is a type of electrical transmission line used to convey. A differential microstrip antenna with improved gain for RF energy harvesting is presented in this paper. 6 mm 0. The port types are set to transverse electromagnetic (TEM) that is configured with electric potential and ground subfeatures. Press Analyze to see the results. 如何在HFSS中建模差分微帶線該視頻向您展示瞭如何在HFSS中創建差分微帶並對其進行建模。 您可以在此處下載該工具包：. In this paper, a compact full Ka-band differential microstrip line (DML) to rectangular waveguide transition is proposed. These radio frequency calculators help with unit conversion, attenuator design, antenna design, radars, and various other basic calculators. Fourth, it classifies differential antennas into wire, slot, microstrip, printed, and dielectric resonator antennas to better present their suitability and functionality. The most important design goal is to keep the wave impedance as homogenous as possible. Unbalanced and balanced (differential) microstrip techniques are discussed for 4-layer PCBs using FR-4. The microstrip calculator determines the width and length of a microstrip line for a given characteristic impedance (Zo). I assigned PerfE boundaries to each microstrip and pad element in yellow. The main difference between these types of traces is their location in the PCB: microstrips are on the surface layer, while striplines are on an inner layer between two reference planes. 1, were developed by Hammerstad. – Striplines are embedded between two reference layers, which results in a higher capacitance versus microstrip lines. Calculates the width of a Microstrip Transmission Line. Firstly, two symmetrical rectangular slots. Differential pairs can be found in various applications such as printed circuit boards, connectors, and cables. The vias must be made to stretch through the entire. 1 Even and Odd Mode Differential microstrip lines support two quasi-TEM modes, that is, the even and odd modes. My fab's standard 1st-to-2nd layer dielectric thickness on FR-4 is 213µm (7628H). Circuit designers classify power loss in microstrip lines into conductor loss, dielectric loss, and radiation loss. 46 mm width traces to obtain 100 Ohms ZDiff while using 0. IEEE Sensors Journal 18 , 5786 – 5793 . 15 mm spacing. This configuration is known to be useful to enhance signal-to-noise ratio. 15 mm spacing. See moreThe Differential microstrip impedance calculator is used to compute the differential (Zd) and single-ended impedance (Zo) of an edge-coupled microstrip line just by entering the width, separation and thickness of. Edge. Source : check_circle. Tagged: Differential, Transmission Line, USB. Microstrip construction consists of a differential pair and a single reference layer (typically ground). Differential surface microstrip with ground calculations: ( This calculator gave a different result, don't know why ) *0. The width of the conductor strip is W, t is the thickness of. Most PCB design tools support such differential pairs. A new microstrip tri-mode balun bandpass filter (BPF) with good filter-type and balun-type functions is presented. The novel DMPA eliminates not only the loss dure to a balun, it also inherits significant advantages from the microstrip line structures, such as low profile, compact size, low cost, simple fabrication. S. 1. This letter presents an analysis of the impedances of differential feed microstrip rectangular patch antennas.